Mardi 19 Avril

Heure:	14:00 - 17:00
Lieu:	Salle B107, bâtiment B, Université de Villetaneuse
Résumé:	On Noncrossing Partitions for the Alternating Groups
Description:	Henri Mühle The lattice of noncrossing set partitions of an n-set can beseen as a subgraph of the Cayley graph of the symmetric group S generated by all transpositions. We mimic thisconstruction for the alternating group A2n+1 generated byall 3-cycles. The resulting poset provides a rich new source ofcombinatorics coming from the alternating groups, which in some senseparallels the combinatorics behind the noncrossing set partitions. Wepresent some enumerative and bijective results, and suggest an extensionof this construction to all finite Coxeter groups. This is joint workwith Philippe Nadeau.