Abstract:
It is proved that, if G is a finite group with a nontrivial normal 2-subgroup Q such that G/Q≅A7 and an element of order 5 from G acts without fixed points on Q, then the extension of G by Q is splittable, Q is an elementary abelian group, and Q is the direct product of minimal normal subgroups of G each of which is isomorphic, as a G/Q-module, to one of the two 4-dimensional irreducible GF(2)A7-modules that are conjugate with respect to an outer automorphism of the group A7.
Keywords:
finite group, GF(2)A7-module, completely reducible representation, prime graph.
Citation:
A. S. Kondrat'ev, I. V. Khramtsov, “The complete reducibility of some GF(2)A7-modules”, Trudy Inst. Mat. i Mekh. UrO RAN, 18, no. 3, 2012, 139–143; Proc. Steklov Inst. Math. (Suppl.), 283, suppl. 1 (2013), 86–90