BEGIN:VCALENDAR METHOD:PUBLISH PRODID:www-math-fau-de//Events//DE VERSION:2.0 BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Quantum Geometry and Resurgence of Enume rative invariants of Calabi-Yau manifolds UID:f4d3469d-a292-47b2-a3b4-64d0d5844c6a DESCRIPTION:Quantum Geometry and Resurgence of Enumerative invariants of Calabi-Yau manifolds Murad Alim (München) Abstract: Enumerative in variants of Calabi-Yau manifolds are most naturally organized in terms of partition functions of physical theories. Higher genus Gromov Witt en invariants of CY threefolds correspond to the expansion coefficient s of a series in a formal parameter which corresponds to the topologic al string coupling. This series is however only asymptotic. I will sho w how the analysis of finite difference equations and Borel summation reveals the piecewise analytic structure behind the asymptotic expansi on. The resulting Stokes jumps of the piecewise analytic structure enc ode another set of enumerative invariants of the threefold\, namely Do naldson-Thomas invariants. DTSTART:20260130T133000Z DTEND:20260130T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Homogeneous varieties with non-reduced s tabilizers UID:b256a799-6cc3-4c84-9321-b8e9c57d277a DESCRIPTION:Homogeneous varieties with non-reduced stabilizers Matilde Maccan (Bochum) Abstract : In this talk\, we start with the fundament al question of classifying homogeneous algebraic varieties\, over an a lgebraically closed field. First\, we look at the projective case (in the literature\, the case of flag varieties)\, namely quotients of the form G/P\, where G is semi-simple and P contains a maximal solvable s ubgroup. Over the complex numbers\, their structure is well-known\, wh ile in positive characteristics new objects emerge\, due to the Froben ius homomorphism and the existence of non-reduced group (schemes). The classification in characteristic at least five was completed by Wenze l\, Haboush and Lauritzen in the 90’\;s\; my contribution consist ed in completing the case of small characteristics. Next\, focusing on their geometry\, we will present a result describing the automorphism group of G/P (as a group scheme)\, generalizing work of Demazure. Fin ally\, we study a slightly more general class of varieties: the horosp herical homogeneous spaces\, namely quotients G/H where H contains a m aximal unipotent. Quite surprisingly\, we find that their classificati on\, in characteristic at least three\, is the same as the one in char acteristic zero. This last result is joint work with R. Terpereau. DTSTART:20260206T110000Z DTEND:20260206T120000Z LOCATION:Übung 1 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Rogers-Ramanujan exact sequences and fre e modules over free generalized vertex algebras UID:64506f35-0c56-4d59-9c77-6fe52ce31ab9 DESCRIPTION:Rogers-Ramanujan exact sequences and free modules over fre e generalized vertex algebras Kazuya Kawasetsu (Kumamoto) Abstract: In this talk\, we introduce the notion of free modules over (generalized ) vertex algebras. A series of recursion formulas\, which generalizes a classical formula used to prove the famous Rogers-Ramanujan (RR) ide ntities and RR continued fraction formula\, is conceptually obtained f rom short exact sequences among free modules over free generalized ver tex algebras\, the RR exact sequences. They include as a special case one equivalent to the exact sequence constructed by S. Capparelli et a l. using intertwining operators in the theory of vertex operator algeb ras. Applications of the RR exact sequences to combinatorics and relat ed areas are given. DTSTART:20260317T133000Z DTEND:20260317T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: On the relative semi-infinite cohomology of graded-unitary vertex operator algebras UID:7e85ce1e-a802-4702-891e-72fee067d905 DESCRIPTION:On the relative semi-infinite cohomology of graded-unitary vertex operator algebras Niklas Garner (Oxford) DTSTART:20260324T133000Z DTEND:20260324T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Modular BGG category O and periodic Kazh dan-Lusztig polynomials UID:f04c5278-344b-4801-afe7-b20d3997176f DESCRIPTION:Modular BGG category O and periodic Kazhdan-Lusztig polyno mials Quan Situ (Clermont-Ferrand) Abstract: We consider a modular ana logue of BGG category O. It is the category of strongly B-equivariant g-modules\, where g is the Lie algebra of a reductive group G over pos itive characteristic and B is a Borel subgroup of G. Its principal blo ck is a highest weight category\, whose underlying poset is the affine Weyl group equipped with the semi-infinite order. We show that the di mension of extension group between simple objects and costandard objec ts is given by the coefficient of periodic Kazhdan-Lusztig polynomials \, when the characteristic is large enough. We will also discuss a con nection to the geometry of semi-infinite orbits on the affine flag var iety. This is based on a joint work with Simon Riche. DTSTART:20260417T123000Z DTEND:20260417T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar Cohomological Hall algebras of 1-dimensio nal sheaves and Yangians over the Bridgeland's space of stability cond itions UID:21dc4737-23d4-4220-be79-1e4e67743e0c DESCRIPTION:Cohomological Hall algebras of 1-dimensional sheaves and Y angians over the Bridgeland’\;s space of stability conditions Fra ncesco Sala (Pisa) Abstract: In this talk\, I will introduce the nilpo tent cohomological Hall algebra COHA(S\, Z) of coherent sheaves on a s mooth quasi-projective complex surface S that are set-theoretically su pported on a closed subscheme Z. This algebra can be viewed as the lar gest algebra of cohomological Hecke operators associated with modifica tions along a subscheme Z of S. When S is the minimal resolution of an ADE singularity and Z is the exceptional divisor\, I will describe ho w to characterize COHA(S\, Z) in terms of the Yangian of the correspon ding affine ADE quiver Q (based on joint work with Emanuel Diaconescu\ , Mauro Porta\, Oliver Schiffmann\, and Eric Vasserot\, arXiv:2603.033 86). More generally\, I will discuss nilpotent COHAs arising from Brid geland stability conditions on the bounded derived category of nilpote nt representations of the preprojective algebra of Q\, following joint work with Olivier Schiffmann and Parth Shimpi (arXiv:2511.08576). DTSTART:20260508T123000Z DTEND:20260508T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Serminar: On quasi-lisse vertex algebras related to regular representations for SL(2) and affine W--algebras UID:aa401b4c-19ac-4fa9-95dc-43671a6aefff DESCRIPTION:On quasi-lisse vertex algebras related to regular represen tations for SL(2) and affine W–\;algebras Drazen Adamovic (Zagreb ) Abstract: We construct a family of potentially quasi-lisse (non-rati onal) vertex algebras\, denoted by $mathcal C_p$\, $p ge 2$\, which ar e closely related to the vertex algebra of chiral differential operato rs on $SL(2)$ at level $k=-2+1/p$. We prove that for $p=3$\, there is an isomorphism between $mathcal C_3$ and the affine vertex algebra $L_ {-5/3}(mathcal g_2)$ from Deligne’\;s series. We establish isomor phisms between $C_p$ and certain affine $W$–\;algebras of types $ F_4$ and $E_8$\, which solve the problems of decompostions of certain conformal embeddings. We also discuss higher rank generalization of ou r construction. This talk is based on joint work with A. Milas DTSTART:20260515T123000Z DTEND:20260515T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar >Dirac Operators and the Representation T heory of Lie Superalgebras UID:739c70e4-dac4-4a21-a36b-2c32a3b245d4 DESCRIPTION:Dirac Operators and the Representation Theory of Lie Super algebras Steffen Schmidt (Odense) DTSTART:20260522T113000Z DTEND:20260522T123000Z LOCATION:01.151-128 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Group schemes and momentum maps UID:9280d665-7c19-4609-bbe9-fdcee6d20546 DESCRIPTION:Group schemes and momentum maps Friedrich Knop Abstract: T est run of my ICM-talk. DTSTART:20260612T123000Z DTEND:20260612T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Feigin-Semikhatov Duality at Large and C ritical Levels UID:bb24a7d5-34a1-4de1-a68c-696fa0113b0c DESCRIPTION:Feigin-Semikhatov Duality at Large and Critical Levels Xua nzhong Dai (Okinawa) DTSTART:20260615T123000Z DTEND:20260615T133000Z LOCATION:Übung 3 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:fec7e741-4769-43ee-8011-2e7ea84121a1 DESCRIPTION:Title: TBA Thibault Juillard (Hamburg) DTSTART:20261113T133000Z DTEND:20261113T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Virasoro type reductions and their inverses UID:736fc77d-57b5-4dc4-affb-37381376edcc DESCRIPTION:Virasoro type reductions and their inverses Justine Fasque l (Melbourne) Abstract: W-algebras form a broad family of vertex algeb ras built from a simple Lie algebra and parametrised by its nilpotent orbits. They are constructed by applying quantum Hamiltonian reduction s to affine vertex algebras\, a sophisticated process that remains lar gely mysterious. Partial and inverse quantum hamiltonian reductions ha ve been introduced to address the intricacies of general reductions. T hey rely respectively on splitting and inverting the reductions. In th is talk\, we will focus on the first example of quantum Hamiltonian re duction —\; which results in constructing the famous Virasoro ver tex algebra —\; and its inverse. We should also mention some appl ications to the representation theory. If time allows\, we will then d iscuss generalisations of the Virasoro partial and inverse reductions to a substantial family of W-algebras associated with height-two nilpo tent orbits. These results were obtained in collaboration with V. Kova lchuk and S. Nakatsuka. DTSTART:20250620T123000Z DTEND:20250620T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Kazhdan-Lusztig equivalence via Soergel bimodules UID:daaa1210-5b6e-468a-98b5-59700cdff045 DESCRIPTION:Kazhdan-Lusztig equivalence via Soergel bimodules Jonathan Gruber Abstract: The category of finite-dimensional representations o f a complex simple Lie algebra admits two canonical non-semisimple def ormations: One is the parabolic BGG category O for an affine Lie algeb ra\, the other is the category of representations of a quantum group a t a root of unity. In a landmark result from the 1990s\, Kazhdan and L usztig have established an equivalence between these non-semisimple ab elian categories. More recently\, Gaitsgory has proposed a conjectural extension of the Kazhdan-Lusztig equivalence to a derived equivalence between the (non-parabolic) BGG category O of the affine Lie algebra and the category of representations of a mixed quantum group. In this talk\, I will establish a variant of the derived equivalence conjectur ed by Gaitsgory\, involving the principal blocks of the aforementioned categories\, by relating the derived categories of these principal bl ocks to categories of Soergel bimodules. I will also explain how this derived equivalence can be used to recover a (non-derived) variant of the Kazhdan-Lusztig equivalence\, again involving the principal blocks . This is joint work with Peter Fiebig\, partly based on recent result s of Ivan Losev and Quan Situ. DTSTART:20250627T123000Z DTEND:20250627T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Universal 2-parameter algebras in VOA theory UID:2aec42d4-7e58-4066-977e-696878d7a058 DESCRIPTION:Universal 2-parameter algebras in VOA theory Vladimir Kova lchuk Abstract: Vertex algebras are a non-commutative and non-associat ive generalization of differential algebras. Of these\, W-algebras for m an important family of finitely (strongly) generated algebras\, defi ned over (a localization) of a polynomial ring in 1 variable. These ca n be organized into families\, based on their (strong) generating type pattern. Such families can be uniformly studied from the perspective of so-called universal 2-parameter algebras\; they are infinitely (str ongly) generated according to a nice pattern\, and defined over a poly nomial ring in 2 variables. We explain why these are nice\, and if tim e permits\, the idea behind their construction. DTSTART:20250704T123000Z DTEND:20250704T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Representation theory of the vertex alge bra of chiral differential operators on a reductive group UID:313a6bdc-f69f-4c39-8629-a4dec702523f DESCRIPTION:Representation theory of the vertex algebra of chiral diff erential operators on a reductive group Damien Simon (Paris) Abstract: et G be a reductive algebraic group. There exists a Kac-Moody version of the usual algebra of differential operators on the group G called the vertex algebra of chiral differential operators on G. The study of the representation theory of this vertex algebra and its various quan tum Hamiltonian reductions allow for a purely vertex algebraic formula tion of the theory of D-modules on loop groups. In turn this allows on e to translate some conjectures coming from the quantum geometric Lang lands program. For generic Kac-Moody levels\, we will explain how to b uild simple objects in therelevant categories that match the expected combinatorics and formulate some conjectures that we check in the case of the multiplicative group. DTSTART:20250711T123000Z DTEND:20250711T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:6615281c-c7b7-4e59-bb1b-46fac9933b76 DESCRIPTION:$chi$-independence for K3 surfaces Paul Ziegler (Regensbur g) Abstract: BPS invariants naturally appear in the enumerative geomet ry of sheaves with one-dimensional support on a Calabi-Yau threefold. Toda conjectured that these invariants are independent of the appearin g Euler characteristic $chi$. I will give an introduction to these con cepts and talk about work in progress with M. Groechenig and D. Wyss p roving this conjecture in the K3 case. We argue by relating BPS cohomo logy to p-adic integration on moduli stacks of sheaves\, for which $ch i$-independence was shown by Carocci-Orecchia-Wyss. For this\, we use a local description of these moduli stacks of sheaves in terms of modu li stacks of quiver representations. DTSTART:20250714T140000Z DTEND:20250714T150000Z LOCATION:Übung 4 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Quantum critical K-theory UID:193c57e0-d213-41db-a87a-0f75c3f87d8b DESCRIPTION:Quantum critical K-theory Gufang Zhao (Melbourne) DTSTART:20250731T121500Z DTEND:20250731T131500Z LOCATION:Übung 4 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Introduction to Supersymmetries in W-algebras UID:aa44f350-aa99-41a0-a5b2-6f807f09cd9b DESCRIPTION:Introduction to Supersymmetries in W-algebras Arim Song Ab stract: W-algebras are vertex algebras constructed via Hamiltonian red uction from Lie (super)algebras. When associated with Lie superalgebra s\, they are expected to exhibit rich structures. One notable conjectu re is that certain families of these W-algebras possess $N=n$ supersym metries. These supersymmetries naturally pair fields within the W-alge bras\, providing a useful framework for understanding their structure. In particular\, for type A Lie superalgebras\, the associated princip al W-algebra was conjectured to have $N=2$ supersymmetry. In recent jo int works\, we have proven this conjecture and further explored the pr operties of the type A principal W-algebra. In this talk\, I will intr oduce the notion of supersymmetries inside vertex algebras. Then\, I w ill present examples of vertex algebras that exhibit such supersymmetr ies. Finally\, I will briefly introduce W-algebras and outline the $N= 2$ supersymmetry of type A principal W-algebras. This talk is based on two joint works: one with Linshaw and Suh\, and the other with Creutz ig\, Kovalchuck\, Linshaw and Suh. DTSTART:20251107T133000Z DTEND:20251107T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Introduction to Supersymmetries in W-alg ebras\, part 2 UID:06c78596-f8b6-4f3d-b1e9-aa500e1a6257 DESCRIPTION:Introduction to Supersymmetries in W-algebras\, part 2 Ari m Song This is a continutation of the talk on 7 November 2025 DTSTART:20251121T133000Z DTEND:20251121T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Proving the logarithmic Kazhdan Lusztig conjecture UID:5d2085ae-49fd-4d3e-8d22-9c5269a37d42 DESCRIPTION:Proving the logarithmic Kazhdan Lusztig conjecture Simon L entner (Hamburg) Abstract: I will review qualitatively how braidings a nd Nichols algebras appear in conformal field theory. Then I present o ur recent proof of the logarithmic Kazhdan Lusztig conjecture: This co njecture roughly 20 years ago by Feigin et. al. state that certain ver tex algebras have a representation category equivalent to the represen tation category of a quantum group. The proof strategy is essentially algebraic and interesting in its own right\, it states that braided te nsor categories of a certain type have to necessarily come from genera lized quantum groups. DTSTART:20251209T140000Z DTEND:20251209T150000Z LOCATION:Übung 3 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Horospherical varieties with quotient si ngularities UID:ce1a42f6-e93a-4063-80a2-30f948ac6401 DESCRIPTION:Horospherical varieties with quotient singularities Sean M onahan (München) Abstract: Quotient singularities are defined as an étale-local property of varieties\, but one can ask if this is actual ly a global property\, possibly when restricted to a particular class of varieties. I am interested in addressing this for horospherical var ieties\, which are a generalization of toric varieties where one repla ces the acting torus with any reductive group. To start\, I will intro duce these horospherical varieties and their known combinatorial theor y via so-called coloured fans\, which generalizes the toric theory usi ng polyhedral fans. Then I will highlight my results: first\, a combin atorial characterization of quotient singularities on these varieties\ ; and second\, a corollary that quotient singularities are indeed a gl obal property in this case. DTSTART:20260109T133000Z DTEND:20260109T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Classical W-algebras via Adler-Gelfand-D ickey realization and Drinfeld-Sokolov reduction UID:13b84099-d9ce-4ab9-88e9-00d4de75d28b DESCRIPTION:Classical W-algebras via Adler-Gelfand-Dickey realization and Drinfeld-Sokolov reduction Uhi Rinn Suh (Seoul) Abstract: Adler an d Gelfand-Dickey constructed integrable systems associated with the cl assical W_n-algebra using a scalar Lax operator of degree n. Later\, D rinfeld Sokolov showed that the same structures can be obtained from a n nxn linear Lax operator. The Drinfeld-Sokolov approach makes it poss ible to clearly observe the structure of the classical principal W-alg ebra for a general reductive Lie algebra and to derive the correspondi ng integrable systems. Subsequently\, De Sole-Kac-Valeri combined the Adler-Gelfand-Dickey and Drinfeld-Sokolov methods to obtain results fo r arbitrary classical W-algebras. In this talk\, I will explain how th ese methods can be extended to classical W-algebras or SUSY W-algebras . DTSTART:20260123T133000Z DTEND:20260123T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Tensor structures for affine Lie algebra s at positive levels UID:ed67f739-ea79-4453-b567-143b15d8dc07 DESCRIPTION:Tensor structures for affine Lie algebras at positive leve ls Jonathan Gruber (FAU) Abstract: An affine Lie algebra g is a centra l extension of the loop algebra of a complex simple Lie algebra\, and a g-module is said to have (relative) level k if the canonical central element acts by the scalar k-h\, where h is the dual Coxeter number. For all levels k that are not positive rational or zero\, Kazhdan and Lusztig have defined a braided monoidal structure on a parabolic BGG c ategory O of g-modules of level k. In this talk\, I will explain the d efinition of a braided monoidal structure on the category O at positiv e rational levels\, via a monoidal enhancement of Brundan and Stroppel ’\;s semi-inifnite Ringel duality. This is based on joint work wi th Johannes Flake and Robert McRae. DTSTART:20241129T133000Z DTEND:20241129T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar:CFT/TFT correspondence beyond semisimplicity UID:28a3b1c6-9ddc-4cb4-a1aa-2dfde09b77e8 DESCRIPTION:CFT/TFT correspondence beyond semisimplicity Aaron Hofer ( Hamburg) Abstract: Since the 1980s it is well known that there is a cl ose relationship between two dimensional conformal field theories and three dimensional topological field theories. This CFT/TFT corresponde nce furnishes a tractable example of holography as well as a first exa mple of the symmetry TFT Framework. The Fuchs-Runkel-Schweigert constr uction is a mathematicaly precise incarnation of this correspondence a nd gives a rigorous construction of correlators for rational CFTs usin g a 3d TFT of Reshetikhin-Turaev type. In this talk I will review the FRS-construction and explain how it can be generalised to non-rational CFTs using the non-semisimple 3d TFTs of De Renzi\, Gainutdinov\, Gee r\, Patureau-Mirand\, and Runkel. DTSTART:20241206T133000Z DTEND:20241206T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Higher algebras and topological quantum field theories UID:fe8ee81f-98d6-4e45-917b-b38e089ed5d3 DESCRIPTION:Higher algebras and topological quantum field theories Nil s Carqueville (Wien) Abstract: Topological quantum field theory is a p lace where algebra\, topology\, category theory and theoretical physic s meet. We give an introduction from a representation theoretic perspe ctive\, and then discuss how actions of (higher) groups and (higher) f usion categories naturally appear in this setting. A unifying umbrella for such examples are algebraic structures called orbifold data. We e xplain their basic topological origin and explore some applications. DTSTART:20241220T133000Z DTEND:20241220T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Deformation Quantization via Categorical Factorization Homology UID:65179dd3-fec5-403d-ad7d-a49b49f5ab3b DESCRIPTION:Deformation Quantization via Categorical Factorization Hom ology Lukas Müller (Perimeter) Abstract: Factorization homology `inte grates‘\; (higher) categorical structures\, such as representatio n categories of Hopf algebras\, VOAs\, or quantum groups\, over manifo lds. In my talk\, I will discuss an approach for constructing local-to -global deformation quantizations of symplectic manifolds\, such as mo duli spaces of flat bundles (character varieties)\, based on factoriza tion homology. In this approach\, local quantizations are governed by E_2​-deformations of symmetric monoidal categories\, which\, when in tegrated over 2-dimensional manifolds\, lead to Poisson structures and deformation quantizations. Applying the general framework to the Drin feld category reproduces deformations previously introduced by Li-Blan d and Ševera. As a direct consequence\, we can conclude a precise rel ation between their quantization and those introduced by Alekseev\, Gr osse\, and Schomerus. No prior knowledge of factorization homology wil l be assumed. The talk is based on joint work with Eilind Karlsson\, C orina Keller\, and Ján Pulmann. DTSTART:20250110T133000Z DTEND:20250110T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: A chromatic decomposition of the equivar iant cohomology of Grassmannians UID:4bdde6bf-7795-4a63-9de5-8f9a6c38a04c DESCRIPTION:A chromatic decomposition of the equivariant cohomology of Grassmannians Peter Fiebig (FAU) 0. It turns out that one can use chr omatic descent in this setup to show that the cohomology decomposes in to a tensor product of lower height cohomologies of fixed point subvar ieties. DTSTART:20250124T133000Z DTEND:20250124T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: On some simple affine VOAs at non-admiss ible level k=-2 UID:1c02cd26-48c2-49a3-b925-09d6dadcacc5 DESCRIPTION:On some simple affine VOAs at non-admissible level k=-2 Ju stine Fasquel (Melbourne) Abstract: It is well known that the exceptio nal Lie algebra G2 can be realized as the orbifold of the Lie algebra D4 by the symmetric group of degree 3 which is its Dynkin diagram auto morphism group. In this talk\, I will discuss how this construction ca n be upgraded for the corresponding simple affine vertex algebras and their associated varieties. This provides a new interesting example sa tisfying a number of conjectures in the context of orbifold vertex alg ebras. Moreover\, we use the associated varieties to extract informati on on the representation theory of the affine vertex algebras and clas sify some of their weight modules. This talk is based on a joint work with Arakawa\, Dai\, Li and Moreau. DTSTART:20250131T133000Z DTEND:20250131T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: The projective functors on the category O UID:33cabfc0-0e09-4da4-ac35-f4f71d3e9d4a DESCRIPTION:The projective functors on the category O Xinrui You (Frei burg) Abstract: Bernstein and Gelfand classified the projective functo rs (i.e. direct summands of the tensor by a finite dimensional represe ntation) on the category of Z-finite modules in 1980. We will discuss the restriction of the projective functors on the category O\, and the connection to Soergel bimodules. DTSTART:20250425T123000Z DTEND:20250425T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Supersymmetric 2d conformal field theory and mirror symmetry UID:6b59b6dd-5e72-4540-a658-992fcada7696 DESCRIPTION:Supersymmetric 2d conformal field theory and mirror symmet ry Yuto Moriwaki (Riken) Abstract: The mirror symmetry of Calabi-Yau m anifolds is a mysterious operation in which the complex and Kähler st ructures are interchanged\, but at the level of supersymmetric 2d conf ormal field theory\, which is the source of its discovery\, it is an o bvious operation corresponding to an external automorphism of the Lie algebra. In this talk\, based on arXiv:2504.09919\, I will explain the mirror symmetry of conformal field theories and propose a new proof m ethod for the existence of mirror Calabi-Yau manifolds. DTSTART:20250502T123000Z DTEND:20250502T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Color factors for sl(N) UID:dbacd855-42ef-47d3-bf99-52b59a5b2e1d DESCRIPTION:Color factors for sl(N) Oliver Schnetz DTSTART:20250509T123000Z DTEND:20250509T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Degenerate Kustin-Miller unprojection an d volume normalization UID:edf5e44b-d31c-49a2-b2e0-a618960fe83d DESCRIPTION:Degenerate Kustin-Miller unprojection and volume normaliza tion Stavros Papadakis (Ioannina) Abstract: Unprojection theory is a g eneral theory\, introduced by Miles Reid\, which aims to construct and /or analyze complicated commutative rings in terms of simpler one. Mot ivated by questions related to simplicial spheres and lattice polytope s\, we will discuss the degenerate Kustin-Miller unprojection. In addi tion\, we will present an application to the volume normalization of t he generic Artinian reduction of a standard graded commutative Gorenst ein algebra. The talk is based on joint work with Karim Adiprasito and Vasiliki Petrotou. DTSTART:20250516T123000Z DTEND:20250516T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Quasi-lisse vertex algebras from quantum hamiltonian reduction UID:49e2ce3b-883c-4d32-81fb-be9e157431d8 DESCRIPTION:Quasi-lisse vertex algebras from quantum hamiltonian reduc tion Xuanzhong Dai (RIMS\, Kyoto) Abstract: In this talk\, we introduc e a quantum Hamiltonian reduction associated with arbitrary semisimple Lie algebras and their representations. We prove that the zeroth coho mology of the global sections obtained via this reduction is always si mple. As an application\, we apply the construction to the chiral diff erential operators on the basic affine space. This is joint work in pr ogress with Tomoyuki Arakawa and Bailin Song. DTSTART:20250613T123000Z DTEND:20250613T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Fouriertransformation und Galoisrealisie rungen spezieller linearer Gruppen UID:bd957503-465a-4cce-becd-684750215c33 DESCRIPTION:Fouriertransformation und Galoisrealisierungen spezieller linearer Gruppen Michael Dettweiler (Bayreuth) DTSTART:20240607T123000Z DTEND:20240607T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Spectral measures in tensor categories a nd applications UID:10055744-cdf1-46b4-adbd-58c1b5ee31bf DESCRIPTION:Spectral measures in tensor categories and applications Em manuel Kowalski (Zürich) Abstract: (joint work with A. Forey and J. F resán) Given an object M of a tensor category\, and a suitable numeri cal invariant (such as the multiplicity of the unit object\, in the se misimple case)\, a spectral measure for M is a positive measure\, if i t exists\, whose moments give the values of the invariant on the tenso r powers of M. We will discuss some of the motivation behind this noti on (coming from number theory)\, as well as examples\, focusing on the case of tensor envelope categories\, where spectral measures lead to new proofs of old results on fixed-point statistics in certain situati ons. We will also mention open questions and speculations. DTSTART:20240621T123000Z DTEND:20240621T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Equivariance and what it buys you UID:daa5d40c-356a-4348-98f1-a1b07cfca38a DESCRIPTION:Equivariance and what it buys you Johan Martens (Edinburgh ) Abstract: We will give an overview of operations in geometry that ar ise out of the symmetry by a compact/reductive group\, focusing on imp losion and contraction. These come in related symplectic\, algebro-geo metric\, and hyperkähler versions. For all of these the crucial examp le is given by the universal version\, obtained by applying the operat ions to the group or its cotangent bundle\, depending on the context. Many of the known examples of symplectic duality arise as universal ve rsions of these operations on the hyperkahler side. This is based on j oint works with Hilgert and Manon\, Dancer and Kirwan\, and Dancer\, G rimminger and Zhong. DTSTART:20240705T123000Z DTEND:20240705T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Feynman integration via representation theory UID:db34a4ef-2a66-4dea-863b-58ceaaa5f24b DESCRIPTION:Feynman integration via representation theory Oliver Schne tz (Hamburg\, Erlangen) DTSTART:20240712T123000Z DTEND:20240712T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Two edge coloring problems in algebraic combinatorics UID:2a6e6392-c134-4071-8e11-96f7ddf57af5 DESCRIPTION:Two edge coloring problems in algebraic combinatorics Robe rt Donley (New York) Abstract: This talk concerns two edge coloring pr oblems\, one for simplices and one for hypercubes. For simplices\, we consider Stanley’\;s conjecture on the existence of a symmetric c hain order for the restricted Young lattices $L(m\, n).$ Using weak co mpositions\, we recast the problem in terms of root systems of type A. For hypercubes\, we give an overview of adinkras in supersymmetry\, c onsidered from the point of view of combinatorial designs\, including perfect matchings and 1-factorizations. We give a new characterization of adinkras using Latin rectangles. DTSTART:20240719T123000Z DTEND:20240719T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: The non-semisimple Kazhdan-Lusztig categ ory for affine sl_2 at admissible levels UID:e194b896-89e3-4808-ac0c-852af43e94f7 DESCRIPTION:The non-semisimple Kazhdan-Lusztig category for affine sl_ 2 at admissible levels Robert McRae (Beijing) Abstract: The Kazhdan-Lu sztig category KL^k(sl_2) is the category of finite-length modules for affine sl_2 at level k whose composition factors are irreducible high est weight modules whose highest weights are dominant integral for the finite -dimensional subalgebra sl_2. In this talk\, we show that for admissible levels k = −2 + p/q\, where p>1 and q>0 are relatively pr ime integers\, KL^k(sl_2) admits the vertex algebraic braided tensor c ategory structure of Huang-Lepowsky-Zhang\, but that it is not rigid\, that is\, not every object has a dual. Instead\, an object of KL^k(sl _2) is rigid if and only if it is projective and\, moreover\, KL^k(sl_ 2) has enough projectives. Most of the indecomposable projective objec ts are logarithmic modules\, which means that the Virasoro L_0 operato r acts non-semisimply. We show also that the monoidal subcategory of r igid and projective objects is tensor equivalent to the category of ti lting modules for quantum sl_2 at the root of unity e^{pi i/(k+2)}. Th is leads to a universal property for KL^k(sl_2)\, which allows us to c onstruct an essentially surjective (but not fully faithful) exact tens or functor from KL^k(sl2) to the category of finite -dimensional weigh t modules for quantum sl_2 at e^{pi i/(k+2)}. This is joint work with Jinwei Yang. DTSTART:20241011T123000Z DTEND:20241011T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Generalized Symmetries and Anomalies in Quantum Field Theory and Quantum Gravity UID:34ff035f-a5d9-434f-bf4c-fc618268b6ec DESCRIPTION:Generalized Symmetries and Anomalies in Quantum Field Theo ry and Quantum Gravity Markus Dierigl (München) Abstract: In this tal k I will discuss the relevance of generalized symmetries and anomalies in the investigation and classification of Quantum Field Theories. In their modern formulation they are implemented by the action of topolo gical symmetry operators and the prescription of how to combine them. Once the theory is coupled to gravity global symmetries\, including th eir generalized versions\, must be absent\, i.e.\, they must be broken or gauged. In both cases the deformation classes of spacetime manifol ds with the associated symmetry structure\, captured by bordism groups \, become relevant. This leads to strong universal consistency conditi ons for the low energy effective theories\, which I will discuss in so me special examples. DTSTART:20241018T123000Z DTEND:20241018T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:17th Seminar on Conformal Field Theory UID:eca6f6e5-5c87-4be1-beb2-2f66dd1c1f7e DESCRIPTION:The speakers of the 17th Seminar on Conformal Field Theory are Thomas Creutzig (FAU Erlangen-Nürnberg)\, Jens Eberhardt (Univ. Wuppertal) and Michael Tuite (Univ. Galway). More information on this webpage. DTSTART:20241025T120000Z DTEND:20241025T160000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: On the structure of W-algebras UID:75163cba-7cf5-44e4-b629-c82acd78b48c DESCRIPTION:On the structure of W-algebras Shigenori Nakatsuka (FAU) A bstract: The W-algebras are vertex algebras obtained from affine Lie a lgebras through quantized Drinfeld-Sokolov reductions parametrized by nilpotent orbits. They are fundamental objects for studying Whittaker models for affine Lie algebras. Recently\, it has been conjectured tha t the W-algebras are organized along the closure relations of nilpoten t orbits: more precisely\, two W-algebras should be reconstructed from each other if the corresponding two nilpotent orbits are in closure r elations. In this talk\, I will discuss the motivation\, the current s tatus of this conjecture\, and various applications to the representat ion theory. The talk is based on several joint works with Creutzig-Fas quel-Linshaw\, Fasquel-Fehily-Fursman\, and Fasquel-Kovalchuk. DTSTART:20241108T133000Z DTEND:20241108T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Regularity theorems for invariant eigend istributions on reductive symmetric spaces UID:881749df-effd-403c-b3ec-2c1955cf95db DESCRIPTION:Regularity theorems for invariant eigendistributions on re ductive symmetric spaces Jannik Michel (Padreborn) Abstract: Harish-Ch andra’\;s celebrated regularity theorem states that a conjugation invariant distribution on a reductive group G which is eigen for the algebra of biinvariant differential operators of G (for example the di stributional character of an irreducible unitary representation) is ne cessarily a locally integrable function on G that is real analytic on the regular set. It is the technical cornerstone on which Harish-Chand ra’\;s original proof of the existence and exhaustion of the disc rete series representations is based upon. In this talk I will present an analogue of Harish-Chandra’\;s regularity theorem for reducti ve symmetric spaces. DTSTART:20241115T133000Z DTEND:20241115T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Introducing inverse hamiltonian reduction UID:d300aab6-7aad-414a-a2a9-8cb63ca41440 DESCRIPTION:Introducing inverse hamiltonian reduction Christopher Raym ond (Hamburg) Abstract: Inverse hamiltonian reduction is a new techniq ue for studying the representation theory of vertex operator algebras (VOAs). In particular\, it provides an explicit method for constructin g simple objects of nonsemisimple nonfinite tensor categories relevant to the study of 2d conformal and 3d topological field theories. I wan t to give an introduction to the ideas at play. No prior knowledge of VOAs is required\, and I will lean heavily on explicit examples coming from the representation theory of (sometimes affine) sl2 and sl3. DTSTART:20241122T133000Z DTEND:20241122T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Category O\, Soergel duality and tilting modules over local noetherian domains UID:3497c599-0363-4635-9509-09d5075e4911 DESCRIPTION:Category O\, Soergel duality and tilting modules over loca l noetherian domains Fabio Lischka Abstract: Many results in the repre sentation theory of semisimple complex Lie algebras can be stated in t he Bernstein-Gelfand-Gelfand category\, or category O for short. In my PhD project\, I study a version of this category –\; written O_A –\; which depends on a local noetherian domain A and is relevant for studying the representation theory of semisimple algebraic groups over algebraically closed fields of positive characteristic. Our goal is to prove that there exists a duality on the subcategory of O_A con sisting of modules which admit a Verma flag. Such a duality has been c onstructed by Soergel for the characteristic 0 case. As an application \, we use this duality to construct a family of infinity-tilting modul es in O_A which generalise the infinity-tilting modules defined by And ersen. DTSTART:20230721T123000Z DTEND:20230721T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:1fd2f9bd-fbec-4cd3-844d-8d45f47fb758 DESCRIPTION:Title: TBA Jonas Stelzig (München) DTSTART:20231009T150000Z DTEND:20231009T160000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Higher operations in complex geometry UID:390e705e-ade8-4ccd-b818-e52b979e049e DESCRIPTION:Title: Higher operations in complex geometry Jonas Stelzig (München) Abstract: In homotopy theory\, higher cohomology operation s (think something like products with more than two ‚\;inputsR 16\;) can be used to classify spaces up to (rational) homotopy equival ence. I will give a survey about this theory and discuss analogous con structions in complex geometry and some related open questions. DTSTART:20231110T133000Z DTEND:20231110T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: On the stability of tangent bundles on r ational surfaces UID:6c2fca51-3bf4-4447-855b-f44e491e81e1 DESCRIPTION:Title: On the stability of tangent bundles on rational sur faces Hendrik Süß (Jena) Abstract: Given a smooth projective variety X one my ask whether its tangent bundle is slope stable with respect to any polarisation. For toric surfaces it has been proved in joint wo rk with Milena Hering and Benjamin Nill that this is the case if and o nly if X is an iterated blowup of the projective plane. One could conj ecture that the same holds more generally for rational surfaces or at least for those among them which admit at least a C*-action. In my tal k I will report on interesting challenges connected to this question a nd on some recent progress obtained in joint work with Valentin Boboc. DTSTART:20231117T133000Z DTEND:20231117T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Solvable subgroups of the automorphism g roup of an affine space UID:5c6a4687-dc8e-4c68-bd73-90e3ba4d2e88 DESCRIPTION:Solvable subgroups of the automorphism group of an affine space Andriy Regeta (Jena) Abstract: The automorphism group Aut(A^n) o f the affine n-space A^n is an infinite-dimensional group if n>1. This group is well studied if n=2\, but very little is known about its str ucture in higher dimensions. In this talk I will discuss some recent p rogress about the structure of Aut(A^n) if n>2 with special emphasis o n the structure of solvable subgroups of Aut(A^n). DTSTART:20231201T133000Z DTEND:20231201T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Darstellungstheorie von Vertex Algebren UID:e8b66216-9c44-427d-bd63-a7773c57a193 DESCRIPTION:Darstellungstheorie von Vertex Algebren Thomas Creutzig (E dmonton) Abstrakt: Integrable Darstellungen einer endlich dimensionale n einfachen Lie Algebra bilden halbeinfache Kategorien. Die grössere Kategorien von Gewichtsmodulen hat hingegen weniger gute Eigenschaften \, z.B. hat es nicht genügend projektive Objekte und schliesst auch n icht unter Tensorprodukt. Affine Lie Algebren sind natürliche unendli ch dimensionale Analoga von endlich dimensionalen Lie Algebren. Vertex Algebren realisieren und verallgemeinern Darstellungen von affinen Li e Algebren. Insbesondere realisieren sie Darstellungskategorien von af finen Lie Algebren mit diversen schönen Eigenschaften wie z.B. Ribbon Tensorstrukturen. Ich möchte einen Überblick über den Stand der Da rstellungstheorie von Vertex Algebren geben. DTSTART:20231218T151500Z DTEND:20231218T161500Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Representations and binomial coefficients UID:22d4be58-6f85-45b7-bb79-f3cc0b56778f DESCRIPTION:Representations and binomial coefficients Peter Fiebig Abs tract: In 2014\, George Lusztig highlighted a particularly puzzling ph enomenon in the representation theory of modular algebraic groups and of quantum groups that led him to suspect that there exist algebraic s tructures beyond quantum groups. In the talk I will give a leisurely e xplanation of this phenomenon and give an overview on recent approache s towards higher quantum groups. However\, none of these approaches wo rk. Not yet. DTSTART:20231222T133000Z DTEND:20231222T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar zum Anlass des Ruhestandes von Prof. Dr. Friedrich Knop UID:3346f235-e583-4de8-8d53-7ac795e1e245 DESCRIPTION:11:30 –\; 12:30 Uhr : The wheel classes in the locall y finite homology of GL_n(Z)\, canonical integrals and zeta values Oli ver Schnetz (Erlangen\, Hamburg) 14:15 –\; 15:15 Uhr : Towards a classification of log-homogeneous varieties Guido Pezzini (Rom) 15:30 –\; 16:30 Uhr : Symmetric quivers and symmetric varieties Martina Lanini (Rom) DTSTART:20240209T103000Z DTEND:20240209T153000Z LOCATION:Hörsaal H13 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Minimal tilting complexes and generic di rect summands of tensor products for reductive algebraic groups UID:154a3468-b88b-41a7-af36-3a12250a0db0 DESCRIPTION:Minimal tilting complexes and generic direct summands of t ensor products for reductive algebraic groups Jonathan Gruber (York) A bstract: Let G be a reductive algebraic group over an algebraically cl osed field of positive characteristic. In this talk\, I will explain a new approach to studying tensor products in the category of rational representations of G\, via minimal complexes of tilting modules. I wil l also explain how this approach allows us to define a new class of in decomposable G-modules\, called generic direct summands\, which appear generically in Krull-Schmidt decompositions of tensor products of sim ple G-modules. DTSTART:20240510T123000Z DTEND:20240510T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Metamorphosis of a Combinatorial Curiosi ty into Geometry UID:36342bc1-c323-491f-a50a-7d1fcb8b0152 DESCRIPTION:Title: Metamorphosis of a Combinatorial Curiosity into Geo metry Mahir Bilen Can (New Orleans) Abstract: Combinatorially motivate d curiosities can sometimes lead to a deeper understanding of specific families of objects in algebraic geometry and representation theory. Indeed\, examples of this phenomenon abound in the literature\, includ ing the fragrant theory of symmetric polynomials\, which directly rela tes to the geometry of various highly symmetric varieties\, such as Gr assmannians and Hilbert schemes. Along these lines\, we will motivate our talk using the curious case of the nearly toric Schubert varieties \, which essentially emerged from our effort to answer the following q uestion: Which orbit closure of a Borel subgroup in a spherical variet y is itself spherical? This is a challenging problem in general. Never theless\, as we will show\, the question possesses an interesting solu tion for Schubert varieties\, guiding us to new conjectures and inspir ing hopes of discovering fresh organizational principles in algebraic group actions. Parts of this talk are based on our collaborative works with Nestor Diaz\, Senthamari Kannan\, and Pinaki Saha. DTSTART:20240517T123000Z DTEND:20240517T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Integer Linear Optimization and Proximit y to Linear Relaxations UID:9ae35e0c-ca48-459d-8ece-57836f1136d2 DESCRIPTION:Integer Linear Optimization and Proximity to Linear Relaxa tions Timm Oertel Abstract: After a short introduction to integer line ar optimization\, I will give an overview over old and new proximity r esults. Where proximity denotes the distance between optimal solutions of integer linear optimization problems and their linear relaxations. As an example\, a classic result by Cook\, Gerards\, Schrijver and Ta rdos bounds proximity in terms of the number of variables and the maxi mum sub determinants of the underlying systems of linear inequalities. More recently proximity has been studied in the context of integer li near programs in standard form. Most notably\, these new bounds do not depend on the number of variables. DTSTART:20230505T123000Z DTEND:20230505T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Representations and Binomial Coefficients UID:8f932c12-8cfb-49ec-85c4-3f8b82fb3080 DESCRIPTION:Representations and Binomial Coefficients Peter Fiebig DTSTART:20230512T123000Z DTEND:20230512T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Tensors of Computational Effects and a L ogic for Probabilistic Traces UID:c99e4a9f-ae5b-4a89-a53d-a43fdd9aa720 DESCRIPTION:Tensors of Computational Effects and a Logic for Probabili stic Traces Sergey Goncharov (FAU) Abstract: Computational effects is a pivotal aspect that distinguishes functions in the mathematical sens e from those\, one uses in programming. Examples of computational effe cts are: non-termination\, non-determinism\, background memory\, input /output\, but also probability\, which is computationally sensible in the context of probabilistic programming. An established way to formal ly capture computational effects is to associate them with (strong) mo nads in the corresponding semantic categories\, in the simplest case & #8212\; in the category of sets and functions. In this category\, mona ds are known to be equivalent to algebraic theories (possibly over ope rations of infinite arities). Combining monads\, and the corresponding theories in a canonical way is an important subject in semantics of p rogramming languages. In this context\, tensors of monads on the one h and correspond to a practically relevant\, universal\, commutative com bination of effects\, and on the other hand tend to yield highly non-t rivial mathematical challenges. In my talk\, I will concentrate on the special case of tensoring countable probability distributions with fr ee theories\, and present recent results on completeness and definabil ity in the corresponding equational logic w.r.t. a natural model of pr obabilistic traces. [This is a joint work with Paul Blain Levy and Nat han Bowler] DTSTART:20230526T123000Z DTEND:20230526T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Fusion quivers UID:cf03d8e9-342a-4fb2-887c-6a141dce107a DESCRIPTION:Fusion Quivers Gregor Schaumann (Würzburg) Abstract: Quiv ers are combinatorial objects with many applications to representation theory\, moduli spaces and (Hopf) algebras. From the point of view of quantum topology it is natural to study monoidal structures on the ca tegories of modules over a given quiver. In this talk we will first ex amine quivers from a categorical point of view\, leading to an accessi ble description of their categories of modules in terms of linear cate gories. Then we discuss a quite general construction of rigid monoidal structures on the modules over a particular class of quivers\, which generalizes in particular the Hopf quivers by Ciblis and Rosso. Finall y we discuss a class of relations on these quivers which are adapted t o the monoidal structures and find for example the Taft Hopf algebra v ia this construction. DTSTART:20230602T123000Z DTEND:20230602T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Klassifikation von R-sphärischen Räume n von Rang 1 UID:96101d27-233b-41a1-b433-26b0d9dce238 DESCRIPTION:Klassifikation von R-sphärischen Räumen von Rang 1 Franz iska Pechtl DTSTART:20230616T123000Z DTEND:20230616T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Darmstadt-Erlangen-Dublin Seminar on CFT and Related Topics (i n Dublin) UID:150eafb1-83b1-4c59-9316-466b13d6a09c DESCRIPTION:The 15th Seminar on Conformal Field Theory and Related Top ics\, co-organized by Peter Fiebig\, takes place on Friday\, June 23\, 2023 in Dublin\, Ireland. More information is available on this webpa ge. DTSTART:20230622T220000Z DTEND:20230622T220000Z DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Geometrische Algebra für Mengen mit Zwi schenrelationen UID:1c1a0b59-fb33-4c0c-8916-3152caef7f3a DESCRIPTION:Geometrische Algebra für Mengen mit Zwischenrelationen Wa lter Wenzel DTSTART:20230630T123000Z DTEND:20230630T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Turaev-Viro-Barrett-Westbury state sums with defects UID:94178cfd-2e6e-4d9e-8958-ff71ebf5cf47 DESCRIPTION:Title: Turaev-Viro-Barrett-Westbury state sums with defect s Catherine Meusburger DTSTART:20221216T133000Z DTEND:20221216T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Multiplicity free U(2)-actions and triangles UID:13922d48-64c0-468b-b5f8-cdef53ee7bd4 DESCRIPTION:Multiplicity free U(2)-actions and triangles Bart Van Stei rteghem Abstract: Multiplicity free actions are the nonabelian general ization of symplectic toric manifolds. I will present joint work with O. Goertsches and N. Wardenski\, in which we concretize F. Knop’\ ;s classification of these actions in case the acting group is U(2) an d the momentum polytope is a triangle. DTSTART:20230113T133000Z DTEND:20230113T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Interpolations of monoidal categories by invariant theory\, part 2 UID:8870c9c1-e8d6-4c15-a5a9-e75fa4c2f025 DESCRIPTION:Interpolations of monoidal categories by invariant theory\ , part 2 Ehud Meir (Aberdeen) Abstract: In this talk I will describe a construction of symmetric monoidal categories by invariant theory inp ut. The construction presented recovers the constructions of Deligne f or categories such as Rep(S_t)\, Rep(O_t) and Rep(Sp_t)\, and the cons tructions of Knop for wreath products with S_t\, and GL_t(O_r)\, where O_r is a finite quotient of a discrete valuation ring. We will also s how how the TQFT categories recently constructed from a rational funct ion by Khovanov\, Ostrik\, and Kononov arise in this context. [part 1 is the colloquium talk on Tuesday\, 17 January 2023] DTSTART:20230120T133000Z DTEND:20230120T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: GKM actions on cohomogeneity one manifolds UID:3d222e1b-88f4-44b0-8507-726fe6348b77 DESCRIPTION:GKM actions on cohomogeneity one manifolds Eugenia Loiudic e (Marburg) We consider compact manifolds M with a cohomogeneity one a ction of a compact Lie group G such that the orbit space M/G is a clos ed interval. For T a maximal torus of G\, we find necessary and suffic ient conditions on the group diagram of M such that the T action on M is of GKM type\, and describe its GKM graph. We apply our method to nu merous examples\; thus we easily establish for instance which of the c ohomogeneity one manifolds with a fixed point\, or of dimension up to six are of GKM type. This is joint work with Oliver Goertsches and Gio vanni Russo. DTSTART:20230127T133000Z DTEND:20230127T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Graded Monads in the Semantics of Concur rent Systems UID:2ae0ac47-794e-47ac-9f0f-009207ab300b DESCRIPTION:Graded Monads in the Semantics of Concurrent Systems Lutz Schröder (FAU) Abstract: Concurrent systems are classically equipped with a range of behavioural equivalences on states that depend on mode ls of interaction with the system\; behavioural equivalences of varyin g granularity are arranged on the famous linear time/branching-time sp ectrum\, with fine-grained branching-time equivalences such as bisimil arity on one end\, and coarse-grained linear-time equivalences such as trace equivalence on the other end. At the same time\, concurrent sys tems vary with regard to their branching type\, which may be\, e.g.\, non-deterministic\, alternating\, probabilistic\, weighted\, or game-b ased. Variation in the system type is captured uniformly in the framew ork of universal coalgebra\; on the other hand\, generic notions of be havioural equivalences provided by the coalgebraic framework have long been limited to branching-time equivalences. Several general approach es to more coarse grained equivalences have emerged recently\; we disc uss an approach via so-called graded monads\, which in universal-algeb raic terms correspond to algebraic theories in which operations are eq uipped with a notion of depth\, and terms and equations are restricted to have uniform depth. In particular\, we will take a look at charact eristic logics and at game-based methods for graded behavioural equiva lences. Time permitting\, we will look beyond behavioural equivalences \, in particular at behavioural preorders and behavioural metrics. DTSTART:20230203T133000Z DTEND:20230203T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Kirillov's orbit method for the Baum-Con nes conjecture for algebraic groups UID:91bd2320-4b10-46f1-9553-d35cf25fbe0f DESCRIPTION:Kirillov’\;s orbit method for the Baum-Connes conject ure for algebraic groups Kang Li Abstract: The orbit method for the Ba um-Connes conjecture was first developed by Chabert and Echterhoff in the study of permanence properties for the Baum Connes conjecture. Tog ether with Nest they were able to apply the orbit method to verify the conjecture for almost connected groups and p-adic groups. In this tal k\, we will discuss how to prove the Baum-Connes conjecture for linear algebraic groups over local fields of positive characteristic along t he same idea. It turns out that the unitary representation theory of u nipotent groups plays an essential role in the proof. As an example\, we will concentrate on the Jacobi group\, which is the semi-direct pro duct of the symplectic group with the Heisenberg group. It is well-kno wn that the Jacobi group has Kazhdans property (T)\, which is an obsta cle to prove the Baum-Connes conjecture. If time permits\, we will als o discuss my recent joint work with Maarten Solleveld about quasi-redu ctive groups. DTSTART:20230210T133000Z DTEND:20230210T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Commuting matrices and Hochschild homology UID:4d9dc038-9034-48e6-b0b8-4ba481943baa DESCRIPTION:Commuting matrices and Hochschild homology Simon Gritschac her (München) Abstract: Let U(n) be the Lie group of unitary n by n m atrices and let C_2(U(n))={(A\,B) in U(n)^2 | AB=BA } be the subspace of U(n)^2 consisting of pairs of commuting matrices. The (singular) ho mology of C_2(U(n)) is rather intricate and seemingly unknown for all n > 2. In this talk I will explain how the equivariant homology of C_2 (U(n)) can be computed using Hochschild homology. I will explain an at tempt to compute the non-equivariant homology and how all of this may be related to the commuting variety in the Lie algebra of U(n). DTSTART:20230428T123000Z DTEND:20230428T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Einhüllende Tensorkategorien I UID:20e0cbf7-98e0-4405-a36f-bffd566343b4 DESCRIPTION:Einhüllende Tensorkategorien I Friedrich Knop DTSTART:20221021T123000Z DTEND:20221021T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Einhüllende Tensorkategorien II UID:b42e9cff-21e5-453f-9ef8-afbe1c31ff07 DESCRIPTION:Einhüllende Tensorkategorien II Friedrich Knop DTSTART:20221028T123000Z DTEND:20221028T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Filtered Frobenius algebras in monoidal categories UID:08503304-c53b-44f2-b292-49aee142164c DESCRIPTION:Filtered Frobenius algebras in monoidal categories Chelsea Walton (Houston) Abstract: In this talk\, I will discuss filtered-gra ded techniques for studying algebras in monoidal categories. The main goal is to establish a categorical version of Bongale’\;s 1967 re sult: A filtered deformation of a Frobenius algebra over a field is Fr obenius as well. Towards the goal\, a monoidal associated graded funct or will be constructed\, and (additional) equivalent conditions for an algebra in a rigid monoidal category to be Frobenius will be examined . Finally I will show\, as an application of our main result\, that an y exact module category over a symmetric finite tensor category C is r epresented by a Frobenius algebra in C. If time permits during the tal k\, I will also propose a few directions for further investigation. Th is is joint work with Harshit Yadav\, available at arXiv:2106.01999. DTSTART:20221111T133000Z DTEND:20221111T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Eilenberg Theorems for Free UID:47391927-4979-4ffd-9399-a7652d0db7db DESCRIPTION:Title: Eilenberg Theorems for Free Stefan Milius (FAU) Abs tract: Algebraic language theory studies the behaviour of finite autom ata of various kinds (e.g.\, regular languages of finite words\, of in finite words\, of trees\, or their weighted variants) in a machine ind ependent way by relating them to finite algebraic structures. This has proved extremely fruitful. For example\, regular languages can be des cribed as the language recognized by finite monoids\, and the decidabi lity of star-freeness rests on Schützenberger’\;s theorem: a reg ular language is star-free iff it is recognized by a finite aperiodic monoid. The backbone of algebraic language theory is formed by more ge neric correspondences of this kind\, called Eilenberg-type corresponde nces\, which relate varieties of languages to pseudovarieties of finit e algebras. There exist more than a dozen Eilenberg-type correspondenc es in the literature today. We show that they all arise from the same recipe: one models languages and the algebras recognizing them by mona ds on an algebraic category\, and applies a Stone-type duality. I will present a variety theorem that covers\, besides Eilenberg’\;s cl assical result\, e.g. Wilke’\;s and Pin’\;s work on infty$ l anguages\, the recent variety theorem for cost functions of Daviaud\, Kuperberg\, and Pin\, and unifies the two categorical approaches of Bo ja’\;nczyk and of Ad’\;amek et al. In addition we derive new results\, such as an extension of the local variety theorem of Gehrke \, Grigorieff\, and Pin from finite to infinite words. DTSTART:20221118T133000Z DTEND:20221118T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:14th Seminar on Conformal Field Theory and Related Topics UID:584085f7-3747-4f1b-90d6-d37603cc6feb DESCRIPTION:The speakers of the 14th Seminar on Conformal Field Theory are Alexandra Zvonareva (University of Stuttgart)\, Sergei Gukov (Cal tech) and Boris Pioline (Sorbonne\, Paris). More information can be fo und at https://www.math.fau.de/14th-seminar-on-conformal-field-theory/ The organizers are Katrin Wendland (Dublin)\, Nils Scheithauer (Darms tadt)\, Peter Fiebig (FAU) DTSTART:20221125T130000Z DTEND:20221125T170000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:939e7191-72d0-447b-b84b-6404b0be9a16 DESCRIPTION:Title: Mirror symmetry and big algebras Tamas Hausel (Klos terneuburg) Abstract: First we discuss the mirror symmetry identificat ion of the coordinate ring of certain very stable upward flows in the Hitchin system and the Kirillov algebra for the minuscule representati on of the Langlands dual group via the equivariant cohomology of the c ominuscule flag variety (e.g. complex Grassmannian). In turn we discus s a conjectural extension of this picture to non-very stable upward fl ows in terms of a big commutative subalgebra of the Kirillov algebra\, which also ringifies the equivariant intersection cohomology of the c orresponding affine Schubert variety. DTSTART:20221202T133000Z DTEND:20221202T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Module categories and generalised 6j sym bols for G-graded vector spaces UID:fbbee688-81fe-4083-8a31-74bdbd19805c DESCRIPTION:Title: Module categories and generalised 6j symbols for G- graded vector spaces Fabio Lischka Abstract: This talk will be based o n my Master’\;s thesis Generalised 6j symbols over the category o f G -graded vector spaces. We will review the notion of module categor ies over a monoidal category and present a basic classification result in the case where the underlying monoidal category is the category of G-graded vector spaces. This serves as preparation to consider the no tions of module functors and module natural transformations\, the main theorem being a classification of simple module functors when G is a finite cyclic group. Monoidal categories\, module categories\, module functors and module natural transformations are of interest as they gi ve rise to so-called generalised 6j symbols\, which can be used to com pute a generalisation of Turaev-Viro invariants for 3-manifolds with d efects\, cf. recent work of Catherine Meusburger. DTSTART:20221209T133000Z DTEND:20221209T143000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Generations of (quantum) tilting modules UID:KOrganizer-1830958241.56 DESCRIPTION:Generations of (quantum) tilting modules Peter Fiebig (ple ase contact bartvs@math for the information to join the online seminar ) DTSTART:20201113T133000Z DTEND:20201113T143000Z LOCATION:Online DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: 2010-2020: a Decade of Quantum Computing UID:KOrganizer-911320068.325 DESCRIPTION:2010-2020: a Decade of Quantum Computing Oliver Schnetz Vo rtrag auf der Konferenz Algebraic Structures in Perturbative Quantum F ield Theory (IHES) Abstract: Supported by Dirk Kreimer\, in 2010 I sta rted analyzing and calculating high loop-order amplitudes in perturbat ive quantum field theory. The main tools were graphical functions\, ge neralized single-valued hyperlogarithms (GSVHs)\, and the c_2-invarian t. I will report on the progress that has been achieved in the past de cade and give a brief account of what might be within reach (of these techniques) in the future. (please contact bartvs@math for the informa tion to join the online seminar) DTSTART:20201120T103000Z DTEND:20201120T112000Z LOCATION:Online DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Eight loops gamma in phi^4 UID:KOrganizer-57236800.198 DESCRIPTION:Eight loops gamma in phi^4 Oliver Schnetz Abstract: We rep ort on a recent calculation of the anomalous dimension gamma in phi^4 theory to loop order eight. The calculation uses graphical functions a nd we focus on the extension of graphical functions to non-integer dim ensions (which is necessary as a means of regularization of divergent Feynman integrals). (please contact bartvs@math for the information to join the online seminar) DTSTART:20210430T123000Z DTEND:20210430T133000Z LOCATION:Online DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Lattice path enumeration for semi-magic squares of size three UID:KOrganizer-420954211.452 DESCRIPTION:Lattice path enumeration for semi-magic squares of size th ree Robert Donley (New York) Abstract: A semi-magic square is a square matrix consisting of non-negative integer entries and such that the s um along any row or column has the same value. For size three\, MacMah on (1916) gave a formula for counting the number of such squares with a fixed line sum. We give a formula for the number of paths from 0 to a given semi-magic square M in the corresponding lattice. In turn\, th is reveals another formula for Clebsch-Gordan coefficients\, which we use to give an efficient algorithm for deriving the 72 Regge symmetrie s. (please contact bartvs@math for the information to join the online seminar) DTSTART:20210723T123000Z DTEND:20210723T133000Z LOCATION:Online DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Unitary braidings UID:a1fceb5b-3bff-4339-96ee-bedf65448b81 DESCRIPTION:Unitary braidings Gandalf Lechner Abstract: The Yang-Baxte r equation is a cubic equation for an endomorphism R (R-matrix) of the tensor square of a vector space V which naturally induces representat ions of braid groups on higher tensor powers of V. In applications in quantum physics\, one is often interested in the situation where V is a finite-dimensional Hilbert space and R is unitary. This talk will re view research aiming at understanding the set of all unitary R-matrice s up to a natural equivalence given by characters of the infinite brai d group. The case of involutive unitary R-matrices\, connected to extr emal characters of the infinite symmetric group\, will be described in some detail. Although the question asked are purely algebraic\, our m ain tools are taken from operator algebras (von Neumann algebras\, sub factors) and quantum field theory. DTSTART:20220527T123000Z DTEND:20220527T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: How to make equations nice UID:ebd4345f-a3fd-4578-8309-4d0782a05999 DESCRIPTION:How to make equations nice Michael Stoll (Bayreuth) Abstra ct: Consider a homogeneous polynomial equation in three variables\, F( X\,Y\,Z) = 0\, with coefficients in the ring of integers. We will pres ent an algorithm that finds an equivalent equation of the form G(X\,Y\ ,Z) := u F(aX+bY+cZ\, dX+eY+fZ\, gX+hY+iZ) = 0 \, where u is a nonzero rational number and (a b c / d e f / g h i) is an invertible matrix w ith rational entries\, such that G also has integral coefficients and the coefficients are more or less as small as possible. This is joint work with Stephan Elsenhans (Würzburg). DTSTART:20220603T123000Z DTEND:20220603T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Pontryagin classes and representations u p to homotopy UID:77c14493-4f91-4a1c-b083-6ab4fdb37bb6 DESCRIPTION:Pontryagin classes and representations up to homotopy Made leine Jotz Lean (Würzburg) Abstract: This talk elaborates on a Theore m by Bott stating that if M is a smooth manifold and F is an involutiv e subbundle of TM of codimension q\, then the k-th Pontryagin classes of the conormal bundle of F have to vanish for k>2q. In fact\, this th eorem can be immediately generalised to a theorem on the Pontryagin cl asses of a reducible vector bundle\, i.e. a vector bundle E over M wit h a flat F connection on E for F an involutive subbundle of TM. In par ticular\, if none of the Pontryagin classes of a given vector bundle v anish\, then it has no quotient to a vector bundle of the same rank ov er a manifold of dimension smaller than dim M/2. We will see the proof of this theorem in the general context of Lie algebroid representatio ns up to homotopy. If time permits\, I will then explain how this give s obstructions to the existence of ideals in Lie algebroids. DTSTART:20220715T123000Z DTEND:20220715T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Clebsch-Gordan coefficients for anti-mag ic squares UID:2fbda8de-653a-4d9f-a124-774b325f8bc4 DESCRIPTION:Clebsch-Gordan coefficients for anti-magic squares Robert Donley (New York) Abstract: There are several ways in which the Clebsc h-Gordan coefficients for SU(2) generalize\, including the series of 3 n-j coefficients\, tensor products of representations for other groups \, and quantum versions of the theory. A central feature of the theory is the poset of semi-magic squares of size three\, which suggests gen eralizations of a combinatorial nature. We will discuss the difficulti es for semi-magic squares of larger size\, including a digression on L atin square enumeration. Instead\, we describe a theory of Clebsch-Gor dan coefficients for the so-called anti-magic squares that retains mos t of the combinatorial features. Part of this work is joint with WonGe un Kim. DTSTART:20220729T123000Z DTEND:20220729T133000Z LOCATION:04.363 DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-1283511337.969 DESCRIPTION:Approaching degenerations in classical Lie types Magdalena Boos (Bochum) Abstract: The Borel subgroup B of a classical Lie group G acts on the nilpotent cone N of nilpotent complex matrices in Lie G via conjugation. If N is restricted to the subvariety of 2-nilpotent matrices\, then the number of orbits is finite and we can describe a p arametrization of the orbits by combinatorial objects. By making use o f a translation to the symmetric representation theory of a finite-dim ensional algebra with self-duality\, we are able to approach their orb it closures. Phenomena which arise in the different classical types wi ll be discussed. This is work in progress with M. Bender\, G. Cerulli Irelli and F. Esposito. DTSTART:20200124T133000Z DTEND:20200124T143000Z LOCATION:Raum Übung 4\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-849480211.848 DESCRIPTION:Tilting Moduln und Quantengruppen Peter Fiebig DTSTART:20200131T133000Z DTEND:20200131T143000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-1237102508.401 DESCRIPTION:The Euler characteristic of Out(F_n) Michael Borinsky (Ams terdam) Abstract: I will report on recent joint work with Karen Vogtma nn on the Euler characteristic of Out(F_n) and the moduli space of gra phs. A similar study has been performed in the seminal 1986 work of Ha rer and Zagier on the Euler characteristic of the mapping class group and the moduli space of curves. I will review a topological field theo ry proof\, due to Kontsevich\, of Harer and Zagier’\;s result and illustrate how an analogous renormalized topological field theory arg ument can be applied to Out(F_n). DTSTART:20200207T133000Z DTEND:20200207T143000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: O. Schnetz UID:KOrganizer-829628300.556 DESCRIPTION:Combinatorial masters in QED Oliver Schnetz (joint with th e Algebraic (and enumerative) combinatorics seminar at the University of Waterloo) (please contact bartvs@math for the data to connect) DTSTART:20200514T140000Z DTEND:20200514T150000Z LOCATION:Online DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: p-DG structures and categorification UID:KOrganizer-541692967.418 DESCRIPTION:p-DG structures and categorification Joshua Sussan (New Yo rk) Abstract: The Jones polynomial is an invariant of links coming fro m the representation theory of quantum groups. After reviewing its con struction\, we will discuss the goals of the categorification program and how the notion of a p-DG algebra naturally arises when looking to categorify the WRT 3-manifold invariant. (please contact bartvs@math f or the data to connect) DTSTART:20200710T123000Z DTEND:20200710T133000Z LOCATION:Online DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: An intertwining operator for dihedral groups UID:KOrganizer-103094838.954 DESCRIPTION:An intertwining operator for dihedral groups Robert Donley (New York) Abstract: In the study of Clebsch-Gordan coefficients for SU(2)\, Regge observed that the domain space consists of semi-magic sq uares of size three and that Clebsch-Gordan coefficients transform in accordance with the usual determinant symmetries. These squares are fa irly well-understood from a combinatorial viewpoint through permutatio n matrices. Changing the point of view to representations of finite gr oups\, we use an intertwining operator on dihedral groups for two purp oses: to determine the generating function for enumerating points on t he corresponding permutation polytopes\, and to give a representation theoretic description of a generalization of the algebra of circulant matrices. (please contact bartvs@math for the information to join the online seminar) DTSTART:20200724T123000Z DTEND:20200724T133000Z LOCATION:Online DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar: Periodizität in der Darstellungstheorie von algebraischen Gruppen und Quantengruppen UID:KOrganizer-447724255.379 DESCRIPTION:Periodizität in der Darstellungstheorie von algebraischen Gruppen und Quantengruppen Peter Fiebig (please contact bartvs@math f or the information to join the online seminar) DTSTART:20201106T133000Z DTEND:20201106T143000Z LOCATION:Online DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-1584283463.97 DESCRIPTION:The graphical function method in 2n-dimensions Michael Bor insky (Amsterdam) Abstract: I will review the graphical function metho d\, developed by Oliver Schnetz\, to perform perturbative calculations in quantum field theory. Moreover\, I will discuss some recent extens ions of the method to arbitrary even dimensions and to tensor valued o bservables. DTSTART:20190918T090000Z DTEND:20190918T100000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-350368985.805 DESCRIPTION:Lefschetz Operatoren und Tilting-Moduln Pieter Fiebig DTSTART:20191025T123000Z DTEND:20191025T133000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-1333252120.634 DESCRIPTION:Hochschild and Poisson (co)homology: finiteness and formal ity Travis Schedler (MPIM & London) Abstract: The Hamiltonian approach views quantum systems as noncommutative formal deformations of classi cal ones\; the first-order part of the deformation is a symplectic or Poisson structure on the classical phase space. Kontsevich’\;s fo rmality theorem famously explains how the deformation theory of the cl assical and quantum systems coincide (the titular Poisson and Hochschi ld cohomology). In cases of smooth symplectic varieties\, this is cont rolled by de Rham cohomology\, which is finite-dimensional. I will sur vey how these finite-dimensionality and formality properties extend\, or do not extend\, to more general (singular\, degenerate\, or orbifol d) situations\, and how to approach these problems using D-modules on the the classical phase space. This includes joint works with Etingof\ , Negron\, and Pym. DTSTART:20191122T100000Z DTEND:20191122T110000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-512009285.778 DESCRIPTION:On the Toral Rank Conjecture and formality Leopold Zoller (München) Abstract: We give an introduction to the Toral Rank Conject ure. It was posed by Steve Halperin roughly 40 years ago and states th at if a compact r-dimensional torus acts freely on a finite CW-complex X\, then the sum of all Betti numbers satisfies dim H*(X\,Q) ≥\; 2r. Using formality and related concepts we explore connections to ot her conjectures and prove the Toral Rank Conjecture in special cases. DTSTART:20191129T133000Z DTEND:20191129T143000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-913568875.891 DESCRIPTION:Cubic surfaces –\; moduli spaces and arithmetic Steph an Elsenhans (Würzburg) Abstract: The study of cubic surfaces and in particular the structure of the 27 lines on the surface is classical. From an arithmetic perspective\, the Galois action on the lines plays an important role. In this talk we will inspect several descriptions o f the moduli space of cubic surfaces. Based on this I will explain how to construct cubic surfaces with a prescribed Galois action on the 27 lines. DTSTART:20191213T133000Z DTEND:20191213T143000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-1465572776.1008 DESCRIPTION:Kählerizability of multiplicity free Hamiltonian manifold s Bart Van Steirteghem DTSTART:20191220T133000Z DTEND:20191220T143000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-1872647843.934 DESCRIPTION:Jordan classes in Lie algebras and algebraic groups Filipp o Ambrosio (Padova) Abstract: Jordan classes of a reductive Lie algebr a are unions of orbits of elements whose Jordan decomposition is simil ar. These objects\, defined by Borho and Kraft\, form a partition of t he Lie algebra into irreducible\, locally closed\, finitely many subva rieties and their closure is a union of Jordan classes. Jordan classes can be defined also for a reductive connected algebraic group and the y enjoy similar properties. The aim of this talk is to describe the lo cal geometry around a point in the closure of a Jordan class in the gr oup by a reduction to the study of Jordan classes in a suitable Lie al gebra. The talk is based on joint work with Giovanna Carnovale and Fra ncesco Esposito. DTSTART:20200117T133000Z DTEND:20200117T143000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-616102301.272 DESCRIPTION:Quadratic refinements of enumerative problems Marc Levine (Essen) Abstract: Using a variety of methods\, ranging from classical algebraic geometry to modern motivic homotopy theory\, a number of cla ssical enumerative invariants\, such as Euler characteristics or count s of rational curves\, have been refined to invariants in the Grothend ieck-Witt ring of quadratic forms. These refinements yield the classic al invariants by taking the rank and signature over the reals. We illu strate the theory with a number of examples. DTSTART:20190524T123000Z DTEND:20190524T133000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-1723538326.835 DESCRIPTION:Riemann surfaces and abelian varieties with automorphisms Sebastián Reyes-Carocca (Temuco) Abstract: In this talk we shall cons ider compact Riemann surfaces (i.e. complex projective algebraic curve s) and complex abelian varieties (i.e. complex tori that are projectiv e) with non-trivial automorphisms. In the first part of the talk we sh all discuss some recent results concerning classification of actions o n Riemann surfaces $S$ and the corresponding isogeny decomposition of the Jacobian varieties $JS$. In the second part we shall discuss a rec ent result related to the topology of the moduli space of (principally polarized) abelian varieties. DTSTART:20190531T123000Z DTEND:20190531T133000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-102371018.997 DESCRIPTION:How to distinguish between symplectic toric manifolds? Mil ena Pabiniak (Köln) Abstract: The heroes in this talk are symplectic toric manifolds\, i.e. manifolds equipped with a closed\, non-degenera te 2-form\, called a symplectic structure\, and many symmetries\, comi ng from an action of a torus of big dimension. By a result of Delzant they are classified by convex polytopes. This correspondence builds a bridge between symplectic geometry and combinatorics of convex polytop es and led to proving many important results on both sides of the brid ge. Delzant’\;s classification is a classification up to equivari ant symplectomorphisms\, i.e. diffeomorphisms respecting not only the symplectic form but also the torus action. A classification of symplec tic toric manifolds up to diffeomorphisms or symplectomorphisms remain s mysterious. We still cannot recognize when two different polytopes c orrespond to the same symplectic manifold equipped with two different toric actions. Masuda and Suh suggested that maybe the integral cohomo logy ring could classify symplectic toric manifolds up to diffeomorphi sms. In this talk I will introduce symplectic toric manifolds\, discus s the well-understood Delzant classification via polytopes and show ho w to calculate the integral cohomology ring of a symplectic toric mani fold from the associated polytope. Then I will pose and partially answ er the following natural question: is any ring isomorphism F: H*(M\;Z) -> H*(N\;Z)\, which maps the class of a symplectic form of M to the c lass of a symplectic form of N\, induced by a symplectomorphism f: N - > M? I will explain how one can use a construction from algebraic geom etry\, called toric degeneration\, to construct required symplectomorp hisms and how such non-equivariant symplectomorphisms affect polytopes associated to the symplectic toric manifolds in question. There will be lots of pictures. The talk is based on a joint work with Sue Tolman . DTSTART:20190607T123000Z DTEND:20190607T133000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-780695269.455 DESCRIPTION:The generatingfunctionology of Clebsch-Gordan coefficients Robert Donley (New York) Abstract: In particle physics\, Clebsch-Gord an coefficients play a central role in the theory of angular momentum\ , where they represent probabilities for coupled systems. By switching from orthonormal bases to ones better suited to representation theory \, one obtains a theory over the integers with a strong combinatorial nature. New features include hexagonal difference tables\, Catalan num bers\, and a partition on the set of 3×\;3 semi-magic squares. DTSTART:20190614T123000Z DTEND:20190614T133000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-1603547335.304 DESCRIPTION:Calabi-Yau metrics on some symmetric spaces Thibaut Delcro ix (Straßburg) Abstract: In this talk\, I will present how\, in a joi nt work with O. Biquard\, we constructed Ricci flat Kähler metrics on some rank two complex symmetric spaces. On compact complex manifolds\ , the existence of such metrics is fully understood by the famous solu tion by Yau of the Calabi conjecture. For non compact manifolds as in our case\, results of existence mostly rely on determining an asymptot ic model. We determined geometrically meaningful asymptotic models in our situation by using the wonderful compactifications of symmetric sp aces. DTSTART:20190628T123000Z DTEND:20190628T133000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-301623508.75 DESCRIPTION:Branching laws for unitary representations of rank one rea l reductive groups Jan Frahm Abstract: Branching laws describe the dec omposition of an irreducible representation of a group into irreducibl e representations for a subgroup. For compact groups one can always de compose unitary representations discretely into direct sums of irreduc ibles\, whereas for non-compact real reductive groups such as GL(n\,R) the decomposition will usually involve a continuous part given by a d irect integral of irreducible unitary representations. I will try to e xplain how such decompositions can be obtained in the context of rank one groups\, and how they depend on the parameters of the representati ons. DTSTART:20190712T123000Z DTEND:20190712T133000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-1391235798.262 DESCRIPTION:Biquotients in symplectic geometry Oliver Goertsches (Marb urg) Abstract: Biquotients are generalizations of homogeneous spaces t hat naturally occur in Riemannian geometry\, mostly in regard to quest ions concerning positive and nonnegative curvature. In this talk we wi ll explain why they are also of interest in symplectic and Kähler geo metry\, by constructing many such structures on equal rank biquotients . Particular emphasis will be put on Eschenburg’\;s twisted flag manifold SU(3)//T\, which we will compare to Tolman’\;s and Woodw ard’\;s examples of symplectic manifolds admitting Hamiltonian no n-Kähler torus actions. (This is joint work with Panagiotis Konstanti s and Leopold Zoller.) DTSTART:20190719T123000Z DTEND:20190719T133000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-247239936.855 DESCRIPTION:Symmetry breaking for strongly spherical real reductive gr oups of rank one Clemens Weiske Abstract: A pair (G\,H) of real reduct ive groups is called strongly spherical if H is a reductive subgroup o f G and (G x H)/diag(H) is real spherical. Then considering representa tions pi of a real reductive algebraic group G and tau of an algebraic reductive subgroup H\, the space Hom_{H}(pi|_{H}\,tau) of H-intertwin ing operators from pi to tau is finite dimensional if and only if (G\, H) is strongly spherical. These operators are called symmetry breaking operators. Restricting to those pairs where G and H are of rank one a nd where pi and tau are spherical principal series representations\, w e classify all symmetry breaking operators explicitly in terms of thei r distribution kernels. This generalizes previous work by Kobayashi 211\;Speh for (G\,H)=(O(1\,n+1)\,O(1\,n)) to the reductive pairs (G\,H ) = (U(1\,n+1\;F)\,U(1\,m+1\;F) x F)\, F=CC\,HH\,OO and F subgroup of U(n-m\;F). DTSTART:20190426T123000Z DTEND:20190426T133000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-148503981.394 DESCRIPTION:Binomial divisibility out to 128 billion Russ Woodroofe (P ristina) Abstract: In earlier work with John Shareshian\, we asked whe ther for every number n\, there are primes p and r so that every nontr ivial binomial coefficient n choose k is divisible by at least one of the two primes. The motivation for the question is from group theory: the question is equivalent to that of whether for every n there are pr imes p\,r so that the alternating group A_n is generated by any Sylow subgroups at p and r. The answer is yes up to a set of asymptotic dens ity zero (assuming the Riemann Hypothesis)\, and we verified it comput ationally out to 1 billion. In more recent work\, joined by Bob Guraln ick\, we have verified computationally that a stronger condition holds for all n out to 128 billion. This computation finishes in about 50 h ours\, which is a great improvement over the 2 weeks that our earlier computation out to 1 billion took. In this talk\, I’\;ll tell you how the question arose in our work. I’\;ll then overview the int erplay between group theory\, number theory\, and computation allowing this computation. DTSTART:20190503T110000Z DTEND:20190503T120000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:42be2f4f-3553-4208-8839-0b9a3ab75ff4 DESCRIPTION:Hochschild cohomology of partial flag varieties Maxim Smir nov (Augsburg) Abstract: The Hochschild-Kostant-Rosenberg decompositio n gives a description of the Hochschild cohomology of a smooth project ive variety in terms of the sheaf cohomology of exterior powers of the tangent bundle. In all but a few cases it is a non-trivial task to co mpute this decomposition\, and understand the extra algebraic structur e which exists on Hochschild cohomology. I will give a general introdu ction to Hochschild cohomology and this decomposition\, and how this p roblem can be studied for partial flag varieties (i.e. varieties of th e form $G/P$ for $G$ a semisimple algebraic group and $P$ a parabolic subgroup)\, in particular for the case of maximal parabolic subgroups (i.e. Grassmannians in type A and their analogues in other types). Thi s is joint work in progress with Pieter Belmans. DTSTART:20190510T123000Z DTEND:20190510T133000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT BEGIN:VEVENT SUMMARY:Emmy-Noether-Seminar UID:KOrganizer-842854381.196 DESCRIPTION:The monoidal center of Deligne’\;s interpolation cate gory Rep(S_t) Johannes Flake (Aachen) Abstract: The representations of the symmetric group on n letters form a semisimple tensor category fo r each natural number n. Pierre Deligne defined a family of monoidal c ategories parametrized by the complex numbers which interpolate those categories in a certain precise sense. I will explain this constructio n and discuss joint work with Robert Laugwitz about the monoidal cente r of Deligne’\;s categories yielding\, in particular\, interpolat ion objects for Yetter–\;Drinfeld modules of the symmetric group and link invariants which interpolate Dijkgraaf–\;Witten invarian ts. DTSTART:20190517T123000Z DTEND:20190517T133000Z LOCATION:Raum 04.363\, Cauerstraße 11\, Erlangen DTSTAMP:20260904T205048Z END:VEVENT END:VCALENDAR