Results 41 to 50 of about 21,830 (196)

An algorithm for an 𝓁2-homological test for the planarity of a graph

open access: yesAKCE International Journal of Graphs and Combinatorics, 2020
Given a finite simple graph Γ, one is able to define the presentation of an associate Coxeter group and construct a CW-complex on which the associated Coxeter group acts.
Elizabeth Donovan, Timothy Schroeder
doaj   +1 more source

The absolute order on the hyperoctahedral group [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2009
The absolute order on the hyperoctahedral group $B_n$ is investigated. It is shown that every closed interval in this order is shellable, those closed intervals which are lattices are characterized and their zeta polynomials are computed. Moreover, using
Myrto Kallipoliti
doaj   +1 more source

Bijections between noncrossing and nonnesting partitions for classical reflection groups [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2009
We present $\textit{type preserving}$ bijections between noncrossing and nonnesting partitions for all classical reflection groups, answering a question of Athanasiadis and Reiner. The bijections for the abstract Coxeter types $B$, $C$ and $D$ are new in
Alex Fink, Benjamin Iriarte Giraldo
doaj   +1 more source

Lattice congruences of the weak order [PDF]

open access: yes, 2004
We study the congruence lattice of the poset of regions of a hyperplane arrangement, with particular emphasis on the weak order on a finite Coxeter group.
A. Björner   +17 more
core   +2 more sources

Bijactions in Cataland [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2014
In this abstract, I will survey the story of two enumerative miracles that relate certain Coxeter-theoretic objects and other poset-theoretic objects. The first miracle relates reduced words and linear extensions, while the second may be thought of as ...
Nathan Williams
doaj   +1 more source

Affine Wa(A4), Quaternions, and Decagonal Quasicrystals

open access: yes, 2013
We introduce a technique of projection onto the Coxeter plane of an arbitrary higher dimensional lattice described by the affine Coxeter group. The Coxeter plane is determined by the simple roots of the Coxeter graph I2 (h) where h is the Coxeter number ...
Ashcroft N. W.   +10 more
core   +1 more source

Chiral Polyhedra Derived from Coxeter Diagrams and Quaternions

open access: yesSultan Qaboos University Journal for Science, 2011
There are two chiral Archimedean polyhedra, the snub cube and snub dodecahedron together with their dual Catalan solids, pentagonal icositetrahedron and pentagonal hexacontahedron.
Mehmet Koca   +2 more
doaj   +1 more source

The Poincare series of the hyperbolic Coxeter groups with finite volume of fundamental domains

open access: yes, 2009
The discrete group generated by reflections of the sphere, or Euclidean space, or hyperbolic space are said to be Coxeter groups of, respectively, spherical, or Euclidean, or hyperbolic type.
Chapovalov, Maxim   +2 more
core   +1 more source

Elements with finite Coxeter part in an affine Weyl group

open access: yes, 2012
Let $W_a$ be an affine Weyl group and $\eta:W_a\longrightarrow W_0$ be the natural projection to the corresponding finite Weyl group. We say that $w\in W_a$ has finite Coxeter part if $\eta(w)$ is conjugate to a Coxeter element of $W_0$.
He, Xuhua, Yang, Zhongwei
core   +2 more sources

Signed Projective Cubes, a Homomorphism Point of View

open access: yesJournal of Graph Theory, EarlyView.
ABSTRACT The (signed) projective cubes, as a special class of graphs closely related to the hypercubes, are on the crossroad of geometry, algebra, discrete mathematics and linear algebra. Defined as Cayley graphs on binary groups, they represent basic linear dependencies.
Meirun Chen   +2 more
wiley   +1 more source

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