On Projective representations of direct product of groups

Sumana Hatui

Let $G=G_1\times G_2$ be a finite group. We know that the second cohomology group $H^2(G,{\mathbb{C}}^{\times })$ is isomorphic to $H^2(G_1,\mathbb C^\times) \times H^2(G_2,\mathbb C^\t…