Tensor products of primitive modules

Abstract.

Let F be a field and, for i = 1,2, let G _i be a group and V _i an irreducible, primitive, finite dimensional FG _i -module. Set G = G ₁ \times G ₂ and $V=V_1\otimes _F V_2$. The main aim of this paper is to determine sufficient conditions for V to be primitive as a G-module. In particular this turns out to be the case if V ₁ and V ₂ are absolutely irreducible and V ₁ is absolutely quasi-primitive. Thus we extend a result of N.S. Heckster, who has shown that V is primitive whenever G is finite and F is the complex field. We also give a characterization of absolutely quasi-primitive modules. Ultimately, our results rely on the classification of finite simple groups.