Présentation fischérienne de certaines extensions non scindées de groupes orthogonaux sur F3

Abstract

In this paper we construct two groups, the nonsplit extensions 3^7.O_7(3).2 and 3^8.O^−_8 (3).2, as subgroups of the group Fi_{24} and the Bimonster respectively. For these two extensions we exhibite a set of generating involutions and we give presentations as 3-transposition groups.

Keywords

• coxeter groups
• extension
• presentation
• 3-transposition groups