The Roquette category of finite p-groups

Serge Bouc (1)

1 LAMFA - Laboratoire Amiénois de Mathématique Fondamentale et Appliquée

Let p be a prime number. This paper introduces the Roquette category R_p of finite p-groups, which is an additive tensor category containing all finite p-groups among its objects. In R_p, every finite p-group P admits a canonical direct summand, called the edge of P. Moreover P splits uniquely as a direct sum of edges of Roquette p-groups, and the tensor structure of R_p can be described in terms of such edges. The main motivation for considering this category is that the additive functors from R_p to abelian groups are exactly the rational p-biset functors. This yields in particular very efficient ways of computing such functors on arbitrary p-groups : this applies to the representation functors R_K, where K is any field of characteristic 0, but also to the functor of units of Burnside rings, or to the torsion part of the Dade group.

Mots clés: p-group; Roquette; rational; biset; genetic

Domaines: Théorie des groupes [math.GR]; Catégories et ensembles [math.CT]; Théorie des représentations [math.RT]

Serge Bouc. The Roquette category of finite p-groups. 2011. ⟨hal-00641018⟩