A class of symmetric difference-closed sets related to commuting involutions - Archive ouverte HAL
Pré-Publication, Document De Travail Année : 2016

A class of symmetric difference-closed sets related to commuting involutions

Une classe d'ensembles qui sont fermés sous l'opération de différence symétrique lié aux involutions commutant

Résumé

Recent research on the combinatorics of finite sets has explored the structure of symmetric difference-closed sets, and recent research in combinatorial group theory has concerned the enumeration of commuting involutions in $S_{n}$ and $A_{n}$. In this article, we consider an interesting combination of these two subjects, by introducing classes of symmetric difference-closed sets of elements which correspond in a natural way to commuting involutions in $S_{n}$ and $A_{n}$. We consider the natural combinatorial problem of enumerating symmetric difference-closed sets consisting of subsets of sets consisting of pairwise disjoint $2$-subsets of $[n]$, and the problem of enumerating symmetric difference-closed sets consisting of elements which correspond to commuting involutions in $A_{n}$. We prove explicit combinatorial formulas for symmetric difference-closed sets of these forms, and we prove a number of conjectured properties related to such sets which had previously been discovered experimentally using the On-Line Encyclopedia of Integer Sequences.
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Dates et versions

hal-01345066 , version 1 (18-07-2016)
hal-01345066 , version 2 (12-12-2016)
hal-01345066 , version 3 (28-01-2017)
hal-01345066 , version 4 (18-03-2017)

Identifiants

  • HAL Id : hal-01345066 , version 2

Citer

John Campbell. A class of symmetric difference-closed sets related to commuting involutions. 2016. ⟨hal-01345066v2⟩
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