A remark on the Schur multiplier of p-groups

For a finite p-group G of order p(n), Green (1956) proved that vertical bar M(G)vertical bar= p(1/2n(n-1)-t(G)), where t(G) >= 0 and M(G) is the Schur multiplier of the group G of Berkovich (1991), Zhou (1994), and Ellis (1999) classified the structure of G, when t(G)=0, 1, t(G)=2 and t(G)=3, respectively. In the present article, we study the subject for t(G)=4 and under some condition we characterize all groups satisfying the above property.