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We generalize the notion of graded posets to what we call sign-graded (labeled) posets. We prove that the $W$-polynomial of a sign-graded poset is symmetric and unimodal. This extends a recent result of Reiner and Welker who proved it for…

Combinatorics · Mathematics 2012-04-18 Petter Branden

In this paper, we introduce a notion of unistructural cluster algebras, for which the set of cluster variables uniquely determines the clusters. We prove that cluster algebras of Dynkin type and cluster algebras of rank 2 are unistructural,…

Representation Theory · Mathematics 2013-07-19 Ibrahim Assem , Ralf Schiffler , Vasilisa Shramchenko

We introduce and develop the theory of UMEL-shellable posets. These are posets equipped with an edge-lexicographical labeling satisfying certain uniformity and monotonicity properties. This framework encompasses classical families of…

Combinatorics · Mathematics 2025-12-22 Basile Coron , Luis Ferroni , Shiyue Li

In this paper, plane polynomial systems having a singular point attracting all orbits in positive time are classified up to topological equivalence. This is done by assigning a combinatorial invariant to the system (a so-called "feasible…

Classical Analysis and ODEs · Mathematics 2018-03-08 José Ginés Espín Buendía , Víctor Jiménez López

Generalizing the notion of a multiplicative inequality among minors of a totally positive matrix, we describe, over full rank cluster algebras of finite type, the cone of Laurent monomials in cluster variables that are bounded as a…

Combinatorics · Mathematics 2024-09-11 Michael Gekhtman , Zachary Greenberg , Daniel Soskin

Young's lattice $L(m,n)$ consists of partitions having $m$ parts of size at most $n$, ordered by inclusion of the corresponding Ferrers diagrams. K. O'Hara gave the first constructive proof of the unimodality of the Gaussian polynomials by…

Combinatorics · Mathematics 2013-03-12 Vivek Dhand

A cluster algebra is a commutative algebra whose structure is decided by a skew-symmetrizable matrix or a quiver. When a skew-symmetrizable matrix is invariant under an action of a finite group and this action is admissible, the folded…

Combinatorics · Mathematics 2022-08-31 Byung Hee An , Eunjeong Lee

We show that cluster algebras do not contain non-trivial units and that all cluster variables are irreducible elements. Both statements follow from Fomin and Zelevinsky's Laurent phenomenon. As an application we give a criterion for a…

Rings and Algebras · Mathematics 2013-05-10 Christof Geiß , Bernard Leclerc , Jan Schröer

Extending the thoroughly studied theory of group stability, we study Ulam stability type problems for associative and Lie algebras; namely, we investigate obstacles to rank-approximation of almost solutions by exact solutions for systems of…

Rings and Algebras · Mathematics 2025-07-11 Tomer Bauer , Guy Blachar , Be'eri Greenfeld

We establish a connection between knot theory and cluster algebras via representation theory. To every knot diagram (or link diagram), we associate a cluster algebra by constructing a quiver with potential. The rank of the cluster algebra…

Representation Theory · Mathematics 2024-05-03 Véronique Bazier-Matte , Ralf Schiffler

We study Newton polytopes of cluster variables in type A_n cluster algebras, whose cluster and coefficient variables are indexed by the diagonals and boundary segments of a polygon. Our main results include an explicit description of the…

Combinatorics · Mathematics 2013-10-03 Adam Kalman

This paper investigates the independence polynomials arising from iterated strong products of cycle graphs, examining their algebraic symmetries and combinatorial structures. Leveraging modular arithmetic and Galois theory, we establish…

Combinatorics · Mathematics 2026-01-13 Todd Hildebrant

We introduce a new family of symmetric polynomials $\mathfrak{G}^{(\mathbf{u},\mathbf{v})}_{\lambda}$ arising from exactly solvable lattice models associated with the quantised loop algebra $\mathcal{U}_{q}(\mathfrak{sl}_{2}[z^\pm])$. The…

Combinatorics · Mathematics 2025-12-05 Ajeeth Gunna , Michael Wheeler , Paul Zinn-Justin

We give necessary and sufficient conditions for an integral polynomial without linear factors to be the characteristic polynomial of an isometry of some even, unimodular lattice of given signature. This gives rise to Hasse principle…

Number Theory · Mathematics 2021-05-11 Eva Bayer-Fluckiger

We consider maps on genus-$g$ surfaces with $n$ (labeled) faces of prescribed even degrees. It is known since work of Norbury that, if one disallows vertices of degree one, the enumeration of such maps is related to the counting of lattice…

Combinatorics · Mathematics 2022-05-17 Timothy Budd

If for any $k$ the $k$-th coefficient of a polynomial $I(G;x)$ is equal to the number of stable sets of cardinality $k$ in the graph $G$, then it is called the independence polynomial of $G$ (Gutman and Harary, 1983). Alavi, Malde, Schwenk…

Combinatorics · Mathematics 2011-01-25 Vadim E. Levit , Eugen Mandrescu

We present an algorithm that takes as input any element $B$ of the loop braid group and constructs a polynomial $f:\mathbb{R}^5\to\mathbb{R}^2$ such that the intersection of the vanishing set of $f$ and the unit 4-sphere contains the…

Geometric Topology · Mathematics 2020-10-08 Benjamin Bode , Seiichi Kamada

Given a simple graph $G$ on $n$ vertices, a subset of vertices $U \subseteq V(G)$ is dominating if every vertex of $V(G)$ is either in $U$ or adjacent to a vertex of $U$. The domination polynomial of $G$ is the generating function whose…

Combinatorics · Mathematics 2021-10-05 Amanda Burcroff , Grace O'Brien

Let $G$ be a linear semisimple Lie group without compact factors. We show that uniform approximate lattices $\Lambda$ arising as regular model sets in $G$ determine the ambient group $G$ in a strong sense. Specifically, for every…

Group Theory · Mathematics 2026-04-03 Arunava Mandal , Shashank Vikram Singh

Let $m$ and $k \geq 2$ be positive integers. We show that polynomial $P = (1+x)^m(1+x^k)$ is strongly unimodal (frequently known as {\it log concave\/}) if and only if $m \geq k^2 -3$; this is also the criterion for $P$ to be merely…

Combinatorics · Mathematics 2018-04-05 David Handelman