On the Schur pair of groups

In this paper, it is shown that (V,X) is a Schur pair if and only if the Baer-invariant of an X-group with respect to V is an X-group. Also, it is proved that a locally X class inherited the Schur pair property of , whenever X is closed with respect to forming subgroup, images and extensions of its members. Subsequently, many interesting predicates about some generalizations of Schur's theorem and Schur multiplier of groups will be concluded.