Journée-séminaire de combinatoire

(équipe CALIN du LIPN, université Paris-Nord, Villetaneuse)

Le 19 avril 2016 à 14h00 en B107, Henri Mühle nous parlera de : On Noncrossing Partitions for the Alternating Groups

Résumé : The lattice of noncrossing set partitions of an n-set can be seen as a subgraph of the Cayley graph of the symmetric group S generated by all transpositions. We mimic this construction for the alternating group A2n+1 generated by all 3-cycles. The resulting poset provides a rich new source of combinatorics coming from the alternating groups, which in some sense parallels the combinatorics behind the noncrossing set partitions. We present some enumerative and bijective results, and suggest an extension of this construction to all finite Coxeter groups. This is joint work with Philippe Nadeau.


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