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# Documents  13F60 | enregistrements trouvés : 9

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## Post-edited  Cluster algebras and categorification - Lecture 1 Amiot, Claire (Auteur de la Conférence) | CIRM (Editeur )

In this course I will first introduce cluster algebras associated with a triangulated surface. I will then focus on representation of quivers, and show the strong link between cluster combinatorics and representation theory. The aim will be to explain additive categorification of cluster algebras in this context. All the notions will be illustrated by examples.

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## Post-edited  Morsifications and mutations Fomin, Sergey (Auteur de la Conférence) | CIRM (Editeur )

I will discuss a connection between the topology of isolated singularities of plane curves and the mutation equivalence of the quivers associated with their morsifications. Joint work with Pavlo Pylyavskyy, Eugenii Shustin, and Dylan Thurston.

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## Multi angle  Skeins, clusters, and character sheaves Jordan, David (Auteur de la Conférence) | CIRM (Editeur )

Skein algebras are certain diagrammatically defined algebras spanned by tangles drawn on the cylinder of a surface, with multiplication given by stacking diagrams. Quantum cluster algebras are certain systems of mutually birational quantum tori whose defining relations are encoded in a quiver drawn on the surface. The category of quantum character sheaves is a $q$-deformation of the category of ad-equivariant $D$-modules on the group $G$, expressed through an algebra $D_q (G)$ of “q-difference” operators on $G$.
In this I talk I will explain that these are in fact three sides of the same coin - namely they each arise as different flavors of factorization homology, and hence fit in the framework of four-dimensional topological field theory.
Skein algebras are certain diagrammatically defined algebras spanned by tangles drawn on the cylinder of a surface, with multiplication given by stacking diagrams. Quantum cluster algebras are certain systems of mutually birational quantum tori whose defining relations are encoded in a quiver drawn on the surface. The category of quantum character sheaves is a $q$-deformation of the category of ad-equivariant $D$-modules on the group $G$, ...

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## Multi angle  Cluster algebras and categorification - Lecture 2 Amiot, Claire (Auteur de la Conférence) | CIRM (Editeur )

In this course I will first introduce cluster algebras associated with a triangulated surface. I will then focus on representation of quivers, and show the strong link between cluster combinatorics and representation theory. The aim will be to explain additive categorification of cluster algebras in this context. All the notions will be illustrated by examples.

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## Multi angle  Cluster algebras and categorification - Lecture 3 Amiot, Claire (Auteur de la Conférence) | CIRM (Editeur )

In this course I will first introduce cluster algebras associated with a triangulated surface. I will then focus on representation of quivers, and show the strong link between cluster combinatorics and representation theory. The aim will be to explain additive categorification of cluster algebras in this context. All the notions will be illustrated by examples.

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## Multi angle  The coherent Satake category Williams, Harold (Auteur de la Conférence) | CIRM (Editeur )

The geometric Satake equivalence identifies the Satake category of a reductive group $G$ - that is, the category of equivariant perverse sheaves on the affine Grassmannian $G_{rG}$ - with the representation category of its Langlands dual group $G^∨$. While the Satake category is topological in nature, it has a poorly understood algebro-geometric cousin: the category of perverse coherent sheaves on $G_{rG}$. This category is not semi-simple and its monoidal product is not symmetric. We show however that it is rigid and admits renormalized r-matrices similar to those appearing in the theory of quantum loop or KLR algebras. Applying the framework developed by Kang-Kashiwara-Kim-Oh in their proof of the dual canonical basis conjecture, we use these results to show that the coherent Satake category of $GL_n$ is a monoidal cluster categorification in the sense of Hernandez-Leclerc. This clarifies the physical meaning of the coherent Satake category: simple perverse coherent sheaves correspond to Wilson-’t Hooft operators in $\mathcal{N} = 2$ gauge theory, just as simple perverse sheaves correspond to ’t Hooft operators in $\mathcal{N} = 4$ gauge theory following the work of Kapustin-Witten. Our results also explain the appearance of identical quivers in the work of Kedem-Di Francesco on $Q$-systems and in the context of BPS quivers. More generally, our construction of renormalized r-matrices works in any chiral $E_1$-category, providing a new way of understanding the ubiquity of cluster algebras in $\mathcal{N} = 2$ field theory: the existence of renormalized r-matrices, hence of iterated cluster mutation, is a formal feature of such theories after passing to their holomorphic-topological twists. This is joint work with Sabin Cautis (arXiv:1801.08111).
The geometric Satake equivalence identifies the Satake category of a reductive group $G$ - that is, the category of equivariant perverse sheaves on the affine Grassmannian $G_{rG}$ - with the representation category of its Langlands dual group $G^∨$. While the Satake category is topological in nature, it has a poorly understood algebro-geometric cousin: the category of perverse coherent sheaves on $G_{rG}$. This category is not semi-simple and ...

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## Multi angle  From $Q$-systems to quantum affine algebras and beyond Kedem, Rinat (Auteur de la Conférence) | CIRM (Editeur )

The theory of cluster algebras has proved useful in proving theorems about the characters of graded tensor products or Demazure modules, via the $Q$-system. Upon quantization, the algebra associated with this system is shown to be related to a quantum affine algebra. Graded characters are related to a polynomial representation of the quantum cluster variables. This immediately suggests a further deformation to the spherical DAHA, quantum toroidal algebras and elliptic Hall algebras.
The theory of cluster algebras has proved useful in proving theorems about the characters of graded tensor products or Demazure modules, via the $Q$-system. Upon quantization, the algebra associated with this system is shown to be related to a quantum affine algebra. Graded characters are related to a polynomial representation of the quantum cluster variables. This immediately suggests a further deformation to the spherical DAHA, quantum ...

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## Multi angle  Preprojective algebras and Cluster categories Iyama, Osamu (Auteur de la Conférence) | CIRM (Editeur )

The preprojective algebra $P$ of a quiver $Q$ has a family of ideals $I_w$ parametrized by elements $w$ in the Coxeter group $W$. For the factor algebra $P_w = P/I_w$, I will discuss tilting and cluster tilting theory for Cohen-Macaulay $P_w$-modules following works by Buan-I-Reiten-Scott, Amiot-Reiten-Todorov and Yuta Kimura.

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## Multi angle  Irreducible equivariant perverse coherent sheaves on affine Grassmannians of type $A$ and dual canonical bases Finkelberg, Michael (Auteur de la Conférence) | CIRM (Editeur )

S. Cautis and H. Williams identified the equivariant K-theory of the affine Grassmannian of $GL(n)$ with a quantum unipotent cell of $LSL(2)$. Under this identification the classes of irreducible equivariant perverse coherent sheaves go to the dual canonical basis.
This is a joint work with Ryo Fujita.

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