Data: 24/04/2017

Palestrante: Matěj Stehlík, Université Grenoble Alpes, França.

Local: UFF, Campus GRAGOATÁ
Sala: 409, Bloco H, 4o. andar
Horário: 13h

Título: Topological bounds on the chromatic number

Resumo: Topological bounds on the chromatic number of graphs originate from Lovasz’s celebrated proof of Kneser’s conjecture in 1977. The general idea is to associate a simplicial complex to a graph, and then to bound the chromatic number of the graph in terms of certain topological invariants of the associated complex. In this talk, we will explore an alternative approach using what we call higher-dimensional projective quadrangulations. We will illustrate this on some classes of graphs such as Kneser graphs, and also show how one of the “classical" topological bounds can be expressed purely in terms of projective quadrangulations.

Observações: This is joint work with Tomas Kaiser.