Abstract :
Let G be a p-group with Frattini subgroup Z of order p, and let Er(G) be the Hochschild-Serre spectral sequence corresponding to the central extension of Z representing G. For every maximal subgroup K of G, we study the map image induced by the transfer map t from H*(K, Zp) to H*(G, Zp). Our results are applied to get some mod p cohomology classes of extra-special p-groups.
