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We provide a characterization of infinite frieze patterns of positive integers via triangulations of an infinite strip in the plane. In the periodic case, these triangulations may be considered as triangulations of annuli. We also give a…

Combinatorics · Mathematics 2015-04-13 Karin Baur , Mark James Parsons , Manuela Tschabold

In this article, we construct SL$_k$-friezes using Pl\"ucker coordinates, making use of the cluster structure on the homogeneous coordinate ring of the Grassmannian of $k$-spaces in $n$-space via the Pl\"ucker embedding. When this cluster…

Rings and Algebras · Mathematics 2021-03-03 Karin Baur , Eleonore Faber , Sira Gratz , Khrystyna Serhiyenko , Gordana Todorov

The aim of this note is to describe a geometric relation between simple plane curve singularities classified by simply laced Cartan matrices and cluster varieties of finite type also classified by the simply laced Cartan matrices. We…

Algebraic Geometry · Mathematics 2024-03-14 Vladimir Fock

We prove that there is an finite number of friezes in type D_n, and we provide a formula to count them. As a corollary, we obtain formulas to count the number of friezes in types B_n, C_n and G_2. We conjecture finiteness (and precise…

Combinatorics · Mathematics 2016-10-20 Bruce Fontaine , Pierre-Guy Plamondon

We give a complete classification of torsion pairs in repetitive cluster categories of type $A_n$, which were defined by Zhu as the orbit categories, via certain configurations of diagonals, called Ptolemy diagrams. As applications, we…

Representation Theory · Mathematics 2023-11-21 Huimin Chang

We give a combinatorial interpretation for certain cluster variables in Grassmannian cluster algebras in terms of double and triple dimer configurations. More specifically, we examine several Gr(3,n) cluster variables that may be written as…

Combinatorics · Mathematics 2024-04-30 Moriah Elkin , Gregg Musiker , Kayla Wright

Frieze patterns of integers were studied by Conway and Coxeter. Let $\mathscr{C}$ be the cluster category of Dynkin type $A_n$. Indecomposables in $\mathscr{C}$ correspond to diagonals in an $(n+3)$-gon. Work done by Caldero and Chapoton…

Representation Theory · Mathematics 2016-02-26 Thomas A. Fisher

We show how a cluster-tilted algebra of finite representation type is related to the corresponding tilted algebra, in the case of algebras defined over an algebraically closed field.

Representation Theory · Mathematics 2007-05-23 Aslak Bakke Buan , Idun Reiten

The homogeneous coordinate ring of the Grassmannian Gr(k,n) has a cluster structure defined in terms of planar diagrams known as Postnikov diagrams. The cluster corresponding to such a diagram consists entirely of Pluecker coordinates. We…

Combinatorics · Mathematics 2020-12-21 Bethany Marsh , Jeanne Scott

This paper reviews a class of univariate piecewise polynomial functions known as discrete splines, which share properties analogous to the better-known class of spline functions, but where continuity in derivatives is replaced by (a…

Statistics Theory · Mathematics 2022-05-26 Ryan J. Tibshirani

We continue the exploration of various appearances of cluster algebras in scattering amplitudes and related topics in physics. The cluster configuration spaces generalize the familiar moduli space ${\mathcal M}_{0,n}$ to finite-type cluster…

High Energy Physics - Theory · Physics 2023-07-13 Song He , Yihong Wang , Yong Zhang , Peng Zhao

Cluster categories and cluster algebras encode two dimensional structures. For instance, the Auslander--Reiten quiver of a cluster category can be drawn on a surface, and there is a class of cluster algebras determined by surfaces with…

Representation Theory · Mathematics 2020-02-19 Peter Jorgensen

The theory of cluster algebras of S. Fomin and A. Zelevinsky has assigned a fan to each Dynkin diagram. Then A. Buan, R. Marsh, M. Reineke, I. Reiten and G. Todorov have generalized this construction using arbitrary quivers on Dynkin…

Quantum Algebra · Mathematics 2007-05-23 Frederic Chapoton

We give a short and elementary proof that every Dynkin diagram admits finitely many (positive integral) friezes. This was originally proven by Gunawan-Muller using the geometry of cluster algebras. The proof here provides an explicit…

Combinatorics · Mathematics 2023-12-19 Greg Muller

Broline, Crowe and Isaacs have computed the determinant of a matrix associated to a Conway-Coxeter frieze pattern. We generalise their result to the corresponding frieze pattern of cluster variables arising from the Fomin-Zelevinsky cluster…

Combinatorics · Mathematics 2020-12-21 Karin Baur , Bethany Marsh

The (usual) Caldero-Chapoton map is a map from the set of objects of a category to a Laurent polynomial ring over the integers. In the case of a cluster category, it maps "reachable" indecomposable objects to the corresponding cluster…

Representation Theory · Mathematics 2018-12-14 Thorsten Holm , Peter Jorgensen

We study the cluster categories arising from marked surfaces (with punctures and non-empty boundaries). By constructing skewed-gentle algebras, we show that there is a bijection between tagged curves and string objects. Applications include…

Representation Theory · Mathematics 2019-02-20 Yu Qiu , Yu Zhou

Cluster algebras are categorified by cluster categories, and $g$-vectors are categorified by the classic index with respect to cluster tilting subcategories. However, the recently introduced completed discrete cluster categories of Dynkin…

Representation Theory · Mathematics 2024-12-17 Francesca Fedele , Peter Jorgensen , Amit Shah

Motivated by Conway and Coxeter's combinatorial results concerning frieze patterns, we sketch an introduction to the theory of cluster algebras and cluster categories for acyclic quivers. The goal is to show how these more abstract theories…

Representation Theory · Mathematics 2024-03-05 Matthew Pressland

We study non-linear differential equations on the punctured formal disc by considering the natural derived enhancements of their spaces of solutions. In particular, by appealing to results of the inverse theory in the calculus of…

Algebraic Geometry · Mathematics 2022-02-15 Emile Bouaziz