Seminario del 2008

Febbraio
28
2008
Prof. Robert Cori
Connected permutations and hypermaps
algebra e geometria
In this lecture I will introduce the notion of hypermap~: a pair of permutations representing the embedding of graphs on surfaces. A nice bijection, due to Ossona de Mendez and Rosenstiehl, showing a coding of hypermaps by connected permutations, will be presented. This will be used to give the structure of a family of polynomials in two variables defined by weighted Dyck paths and whose coefficients are related to Stirling numbers.
organizzato da: Marilena Barnabei

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