Results 31 to 40 of about 342 (179)

Projection of Polyhedra onto Coxeter Planes Described with Quaternions

open access: yesSultan Qaboos University Journal for Science, 2015
3-dimensional convex uniform polyhedra have been projected onto their corresponding Coxeter planes defined by the simple roots of the Coxeter diagram ,
Mudhahir Al-Ajmi   +2 more
doaj   +1 more source

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

Completely positive maps for imprimitive complex reflection groups

open access: yesKarpatsʹkì Matematičnì Publìkacìï, 2021
In 1994, M. Bożejko and R. Speicher proved the existence of completely positive quasimultiplicative maps from the group algebra of Coxeter groups to the set of bounded operators.
H. Randriamaro
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

On the rank of a Coxeter group

open access: yesJournal of Group Theory, 2009
Let W be a Coxeter group with Coxeter generators S. The rank of the Coxeter system (W,S) is the cardinality |S| of S. The Coxeter system (W,S) has finite rank if and only if W is finitely generated. If (W,S) has infinite rank, then |S| = |W|, since every element of W is represented by a finite product of elements of S.
Mihalik, Michael L., Ratcliffe, John G.
openaire   +3 more sources

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

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

Signed Projective Cubes, a Homomorphism Point of View

open access: yesJournal of Graph Theory, Volume 113, Issue 1, Page 38-56, September 2026.
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

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

On excess in finite Coxeter groups [PDF]

open access: yesJournal of Pure and Applied Algebra, 2015
For a finite Coxeter group $W$ and $w$ an element of $W$ the `excess' of $w$ is defined to be $e(w) = \min\{\ell(x) + \ell(y) - \ell(w) \; | \; w=xy, \; x^2 = y^2 = 1\}$ where $\ell$ is the length function on $W$. Here we investigate the behaviour of $e(w)$, and a related concept reflection excess, when restricted to standard parabolic subgroups of $W$.
Hart, Sarah B.   +1 more
openaire   +4 more sources

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