Results 51 to 60 of about 11,738 (234)
, 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
Centrality of star and monotone factorisations
Bulletin of the London Mathematical Society, EarlyView.Abstract A factorisation problem in the symmetric group is central if conjugate permutations always have the same number of factorisations. We give the first fully combinatorial proof of the centrality of transitive star factorisations that is valid in all genera, which answers a natural question of Goulden and Jackson from 2009.
Jesse Campion Loth, Amarpreet Rattan
wiley +1 more source
Extremal, enumerative and probabilistic results on ordered hypergraph matchings
Forum of Mathematics, SigmaAn ordered r-matching is an r-uniform hypergraph matching equipped with an ordering on its vertices. These objects can be viewed as natural generalisations of r-dimensional orders.
Michael Anastos +3 more
doaj +1 more source
A survey of subdivisions and local $h$-vectors [PDF]
, 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.
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Chordal Graphs, Even‐Hole‐Free Graphs and Sparse Obstructions to Bounded Treewidth
Journal of Graph Theory, Volume 110, Issue 3, Page 351-365, November 2025.ABSTRACT Even‐hole‐free graphs pose a central challenge in identifying hereditary classes of bounded treewidth. We investigate this matter by presenting and studying the following conjecture: for an integer t ≥ 4 and a graph H, every even‐hole‐free graph of large enough treewidth has an induced subgraph isomorphic to either K t or H, if (and only if) H
Sepehr Hajebi
wiley +1 more source
On the Structure of Bispecial Sturmian Words
, 2013 A balanced word is one in which any two factors of the same length contain the same number of each letter of the alphabet up to one. Finite binary balanced words are called Sturmian words.
Fici, Gabriele
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Journal of Combinatorial Designs, Volume 33, Issue 10, Page 379-387, October 2025.ABSTRACT The E ( s 2 )‐optimal and minimax‐optimal supersaturated designs (SSDs) with 12 rows, 11 q columns, and s max = 4 are enumerated in a computer search: there are, respectively, 34, 146, 0, 3, and 1 such designs for q = 2 , 3 , 4 , 5, and 6. Cheng and Tang proved that for q > 6, there are no such SSDs.
Luis B. Morales
wiley +1 more source
Symmetric 2‐ ( 35 , 17 , 8 ) Designs With an Automorphism of Order 2
Journal of Combinatorial Designs, Volume 33, Issue 10, Page 399-403, October 2025.ABSTRACT The largest prime p that can be the order of an automorphism of a 2‐ ( 35 , 17 , 8 ) design is p = 17, and all 2‐ ( 35 , 17 , 8 ) designs with an automorphism of order 17 were classified by Tonchev. The symmetric 2‐ ( 35 , 17 , 8 ) designs with automorphisms of an odd prime order p < 17 were classified in Bouyukliev, Fack and Winne and ...
Sanja Rukavina, Vladimir D. Tonchev
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Globally nilpotent differential operators and the square Ising model
, 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
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Abundant Neighborhoods, Two‐Sided Markets, and Maximal Matchings
Naval Research Logistics (NRL), Volume 72, Issue 7, Page 1022-1035, October 2025.ABSTRACT I introduce a new graph‐theoretic property called abundant neighborhoods. This property is motivated by studying the thickness of economic markets. A vertex is, roughly, guaranteed to match if and only if it has an abundant neighborhood.
Muhammad Maaz
wiley +1 more source