Results 61 to 70 of about 159,494 (239)

The absolute order on the hyperoctahedral group [PDF]

open access: yes, 2009
The absolute order on the hyperoctahedral group $B_n$ is investigated. It is proved that the order ideal of this poset generated by the Coxeter elements is homotopy Cohen-Macaulay and the M\"obius number of this ideal is computed.
Kallipoliti, Myrto
core   +5 more sources

Coloured shuffle compatibility, Hadamard products, and ask zeta functions

open access: yesBulletin of the London Mathematical Society, EarlyView.
Abstract We devise an explicit method for computing combinatorial formulae for Hadamard products of certain rational generating functions. The latter arise naturally when studying so‐called ask zeta functions of direct sums of modules of matrices or class‐ and orbit‐counting zeta functions of direct products of nilpotent groups.
Angela Carnevale   +2 more
wiley   +1 more source

Conformal Hypergraphs: Duality and Implications for the Upper Clique Transversal Problem

open access: yesJournal of Graph Theory, Volume 109, Issue 4, Page 466-480, August 2025.
ABSTRACT Given a hypergraph ℋ, the dual hypergraph of ℋ is the hypergraph of all minimal transversals of ℋ. The dual hypergraph is always Sperner, that is, no hyperedge contains another. A special case of Sperner hypergraphs are the conformal Sperner hypergraphs, which correspond to the families of maximal cliques of graphs.
Endre Boros   +3 more
wiley   +1 more source

Ising n-fold integrals as diagonals of rational functions and integrality of series expansions

open access: yes, 2013
We show that the n-fold integrals $\chi^{(n)}$ of the magnetic susceptibility of the Ising model, as well as various other n-fold integrals of the "Ising class", or n-fold integrals from enumerative combinatorics, like lattice Green functions, correspond
Bostan, A.   +4 more
core   +2 more sources

Optimal Zero‐Free Regions for the Independence Polynomial of Bounded Degree Hypergraphs

open access: yesRandom Structures &Algorithms, Volume 66, Issue 4, July 2025.
ABSTRACT In this paper, we investigate the distribution of zeros of the independence polynomial of hypergraphs of maximum degree Δ$$ \Delta $$. For graphs, the largest zero‐free disk around zero was described by Shearer as having radius λs(Δ)=(Δ−1)Δ−1/ΔΔ$$ {\lambda}_s\left(\Delta \right)={\left(\Delta -1\right)}^{\Delta -1}/{\Delta}^{\Delta ...
Ferenc Bencs, Pjotr Buys
wiley   +1 more source

Cyclic derangements [PDF]

open access: yes, 2010
A classic problem in enumerative combinatorics is to count the number of derangements, that is, permutations with no fixed point. Inspired by a recent generalization to facet derangements of the hypercube by Gordon and McMahon, we generalize this problem
Assaf, Sami H.
core   +3 more sources

Globally nilpotent differential operators and the square Ising model

open access: yes, 2008
We recall various multiple integrals related to the isotropic square Ising model, and corresponding, respectively, to the n-particle contributions of the magnetic susceptibility, to the (lattice) form factors, to the two-point correlation functions and ...
Bostan, A.   +5 more
core   +3 more sources

Moduli of finite flat torsors over nodal curves

open access: yesJournal of the London Mathematical Society, Volume 112, Issue 1, July 2025.
Abstract We show that log flat torsors over a family X/S$X/S$ of nodal curves under a finite flat commutative group scheme G/S$G/S$ are classified by maps from the Cartier dual of G$G$ to the log Jacobian of X$X$. We deduce that fppf torsors on the smooth fiberss of X/S$X/S$ can be extended to global log flat torsors under some regularity hypotheses.
Sara Mehidi, Thibault Poiret
wiley   +1 more source

Orthogonal Arrays: A Review

open access: yesWIREs Computational Statistics, Volume 17, Issue 2, June 2025.
A four‐run orthogonal array for three two‐level factors. ABSTRACT Orthogonal arrays are arguably one of the most fascinating and important statistical tools for efficient data collection. They have a simple, natural definition, desirable properties when used as fractional factorials, and a rich and beautiful mathematical theory.
C. Devon Lin, John Stufken
wiley   +1 more source

A survey of subdivisions and local $h$-vectors [PDF]

open access: yes, 2015
The enumerative theory of simplicial subdivisions (triangulations) of simplicial complexes was developed by Stanley in order to understand the effect of such subdivisions on the $h$-vector of a simplicial complex.
Athanasiadis, Christos A.
core  

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