Results 31 to 40 of about 177 (130)
Geometric realizations of the s‐weak order and its lattice quotients
Journal of the London Mathematical Society, Volume 112, Issue 3, September 2025.Abstract For an n$n$‐tuple s${\bm{s}}$ of nonnegative integers, the s${\bm{s}}$‐weak order is a lattice structure on s${\bm{s}}$‐trees, generalizing the weak order on permutations. We first describe the join irreducible elements, the canonical join representations, and the forcing order of the s${\bm{s}}$‐weak order in terms of combinatorial objects ...
Eva Philippe, Vincent Pilaud
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The characteristic polynomials of subarrangements of Coxeter arrangements
Discrete Mathematics, 1997 In \(R^n\), a subspace arrangement is a finite collection of subspaces. Such an arrangement generates an intersection lattice, and (via the Möbius function of that lattice) a characteristic polynomial. The author uses a method due to Blass and Sagan to determine and study several such polynomials.
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The Shi variety corresponding to an affine Weyl group
Bulletin of the London Mathematical Society, Volume 57, Issue 3, Page 913-940, March 2025.Abstract Let W$W$ be an irreducible Weyl group and Wa$W_a$ its affine Weyl group. In this article we show that there exists a bijection between Wa$W_a$ and the integral points of an affine variety, denoted X̂Wa$\widehat{X}_{W_a}$, which we call the Shi variety of Wa$W_a$.
Nathan Chapelier‐Laget
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Bergman Complexes, Coxeter Arrangements, and Graph Associahedra
, 2005 Tropical varieties play an important role in algebraic geometry. The Bergman complex B(M) and the positive Bergman complex B+(M) of an oriented matroid M generalize to matroids the notions of the tropical variety and positive tropical variety associated to a linear ideal.
Ardila, Federico +2 more
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Coxeter transformation groups and reflection arrangements in smooth manifolds [PDF]
Journal of Homotopy and Related Structures, 2015 18 pages, 2 figures. V2: minor changes, typos fixed.
Das, Ronno, Deshpande, Priyavrat
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Hurwitz numbers for reflection groups III: Uniform formulae
Journal of the London Mathematical Society, Volume 111, Issue 3, March 2025.Abstract We give uniform formulae for the number of full reflection factorizations of a parabolic quasi‐Coxeter element in a Weyl group or complex reflection group, generalizing the formula for the genus‐0 Hurwitz numbers. This paper is the culmination of a series of three.
Theo Douvropoulos +2 more
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CAT(0) and cubulated Shephard groups
Journal of the London Mathematical Society, Volume 111, Issue 1, January 2025.Abstract Shephard groups are common generalizations of Coxeter groups, Artin groups, and graph products of cyclic groups. Their definition is similar to that of a Coxeter group, but generators may have arbitrary order rather than strictly order 2. We extend a well‐known result that Coxeter groups are CAT(0)$\mathrm{CAT}(0)$ to a class of Shephard ...
Katherine M. Goldman
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Deformations of Coxeter hyperplane arrangements and their characteristic polynomials [PDF]
Advanced Studies in Pure Mathematics, 2018 Let A be a Coxeter hyperplane arrangement, that is the arrangement of reflecting hyperplanes of an irreducible finite Coxeter group. A deformation of A is an affine arrangement each of whose hyperplanes is parallel to some hyperplane of A. We survey some of the interesting combinatorics of classes of such arrangements, reflected in their characteristic
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The excedance quotient of the Bruhat order, quasisymmetric varieties, and Temperley–Lieb algebras
Journal of the London Mathematical Society, Volume 110, Issue 4, October 2024.Abstract Let Rn=Q[x1,x2,…,xn]$R_n=\mathbb {Q}[x_1,x_2,\ldots ,x_n]$ be the ring of polynomials in n$n$ variables and consider the ideal ⟨QSymn+⟩⊆Rn$\langle \mathrm{QSym}_{n}^{+}\rangle \subseteq R_n$ generated by quasisymmetric polynomials without constant term. It was shown by J. C. Aval, F. Bergeron, and N. Bergeron that dim(Rn/⟨QSymn+⟩)=Cn$\dim \big
Nantel Bergeron, Lucas Gagnon
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Valuative invariants for large classes of matroids
Journal of the London Mathematical Society, Volume 110, Issue 3, September 2024.Abstract We study an operation in matroid theory that allows one to transition a given matroid into another with more bases via relaxing a stressed subset. This framework provides a new combinatorial characterization of the class of (elementary) split matroids.
Luis Ferroni, Benjamin Schröter
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