Journée-séminaire de combinatoire

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

Le 08 décembre 2015 à 14h00 en B107, Luca Lionni nous parlera de : Colored triangulations of arbitrary dimensions are stuffed Walsh maps

Résumé : Regular D-edge-colored graphs encode D-dimensional colored triangulations of pseudo-manifolds. We study such families of edge-colored graphs built from a finite but arbitrary set of building blocks, which extend the notion of p-angulations to arbitrary dimensions. I will introduce a bijection between any such family and some colored combinatorial maps which we call stuffed Walsh maps. Those maps generalize Walsh's representation of hypermaps as bipartite maps, by replacing the vertices which correspond to hyperedges with non-properly-edge-colored maps.

We are interested in the number of bi-chromatic cycles of the initial edge-colored graphs because because they encode the curvature of the corresponding triangulated pseudo-manifold. I will therefore present new tools that use the bijection in order to study the graphs which maximize the number of bi-chromatic cycles at fixed number of vertices and provide examples where the corresponding stuffed Walsh maps can be completely characterized.

 [arXiv]


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