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This is an introductory survey on cluster algebras and their (additive) categorification using derived categories of Ginzburg algebras. After a gentle introduction to cluster combinatorics, we review important examples of coordinate rings…

Representation Theory · Mathematics 2012-03-14 Bernhard Keller

We observe that the expansion in the basis of Schubert cycles for $H^*(G/B)$ of the class of a Richardson variety stable under a spherical Levi subgroup is described by a theorem of Brion. Using this observation, along with a combinatorial…

Combinatorics · Mathematics 2013-02-14 Benjamin J. Wyser

A theorem of Ryan and Wolper states that a type A Schubert variety is smooth if and only if it is an iterated fibre bundle of Grassmannians. We extend this theorem to arbitrary finite type, showing that a Schubert variety in a generalized…

Algebraic Geometry · Mathematics 2017-02-10 Edward Richmond , William Slofstra

We develop a general approach to finding combinatorial models for cluster algebras. The approach is to construct a labeled graph called a framework. When a framework is constructed with certain properties, the result is a model…

Combinatorics · Mathematics 2026-05-28 Nathan Reading , David E Speyer

Cluster algebras are a recent topic of study and have been shown to be a useful tool to characterize structures in several knowledge fields. An important problem is to establish whether or not a given cluster algebra is of finite type.…

Commutative Algebra · Mathematics 2015-07-15 Elisângela Silva Dias , Diane Castonguay

Postnikov's plabic graphs in a disk are used to parametrize totally positive Grassmannians. In recent years plabic graphs have found numerous applications in math and physics. One of the key features of the theory is the fact that if a…

Combinatorics · Mathematics 2018-04-09 Sunita Chepuri

Kazhdan-Lusztig ideals, a family of generalized determinantal ideals investigated in [Woo-Yong '08], provide an explicit choice of coordinates and equations encoding a neighbourhood of a torus-fixed point of a Schubert variety on a type A…

Combinatorics · Mathematics 2012-07-31 Alexander Woo , Alexander Yong

By extending the notion of grid classes to include infinite grids, we establish a structural characterisation of the simple permutations in Av(4231, 35142, 42513, 351624), a pattern class which has three different connections with algebraic…

Combinatorics · Mathematics 2013-12-13 Michael H. Albert , Robert Brignall

A major direction in the theory of cluster algebras is to construct (quantum) cluster algebra structures on the (quantized) coordinate rings of various families of varieties arising in Lie theory. We prove that all algebras in a very large…

Quantum Algebra · Mathematics 2015-08-14 K. R. Goodearl , M. T. Yakimov

Using heuristics from mirror symmetry, combinations of Gross, Hacking, Keel, Kontsevich, and Siebert have given combinatorial constructions of canonical bases of "theta functions" on the coordinate rings of various log Calabi-Yau spaces,…

Algebraic Geometry · Mathematics 2021-05-31 Travis Mandel

Plabic graphs are interesting combinatorial objects used to study the totally nonnegative Grassmannian. Faces of plabic graphs are labeled by $k$-element sets of positive integers, and a collection of such $k$-element sets are the face…

Combinatorics · Mathematics 2014-05-21 SuHo Oh , David E Speyer

We prove that any skew-symmetrizable cluster algebra is unistructural, which is a conjecture by Assem, Schiffler, and Shramchenko. As a corollary, we obtain that a cluster automorphism of a cluster algebra $\mathcal A(\mathcal S)$ is just…

Representation Theory · Mathematics 2020-04-22 Peigen Cao , Fang Li

Cluster algebra structures for Grassmannians and their (open) positroid strata are controlled by a Postnikov diagram D or, equivalently, a dimer model on the disc, as encoded by either a bipartite graph or the dual quiver (with faces). The…

Representation Theory · Mathematics 2024-03-15 İlke Çanakçı , Alastair King , Matthew Pressland

In this paper, we prove some combinatorial results on generalized cluster algebras. To be more precisely, we prove that (i) the seeds of a generalized cluster algebra $\mathcal A(\mathcal S)$ whose clusters contain particular cluster…

Rings and Algebras · Mathematics 2019-10-09 Peigen Cao , Fang Li

We study the dependence of a cluster algebra on the choice of coefficients. We write general formulas expressing the cluster variables in any cluster algebra in terms of the initial data; these formulas involve a family of polynomials…

Rings and Algebras · Mathematics 2007-05-23 Sergey Fomin , Andrei Zelevinsky

We show that braid varieties for any complex simple algebraic group $G$ are cluster varieties. This includes open Richardson varieties inside the flag variety $G/B$.

Algebraic Geometry · Mathematics 2025-11-07 Pavel Galashin , Thomas Lam , Melissa Sherman-Bennett

We complete classification of mutation-finite cluster algebras by extending the technique derived by Fomin, Shapiro, and Thurston to skew-symmetrizable case. We show that for every mutation-finite skew-symmetrizable matrix a diagram…

Combinatorics · Mathematics 2019-10-25 Anna Felikson , Michael Shapiro , Pavel Tumarkin

We prove in type A a conjecture which describes the ideal of transversal slices to spherical Schubert varieties in the affine Grassmannian. As a corollary, we prove a modular description (due to Finkelberg-Mirkovi\'c) of the spherical…

Representation Theory · Mathematics 2016-11-22 Joel Kamnitzer , Dinakar Muthiah , Alex Weekes , Oded Yacobi

We prove a conjecture of Knutson asserting that the Schubert structure constants of the cohomology ring of a two-step flag variety are equal to the number of puzzles with specified border labels that can be created using a list of eight…

Combinatorics · Mathematics 2016-06-28 Anders Skovsted Buch , Andrew Kresch , Kevin Purbhoo , Harry Tamvakis

We introduce several commutative rings, the snake rings, that have strong connections to cluster algebras. The elements of these rings are residue classes of unions of certain labeled graphs that were used to construct canonical bases in…

Combinatorics · Mathematics 2015-07-07 Ilke Canakci , Ralf Schiffler
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