Schur multipliers and power endomorphisms of groups

We obtain new bounds for the exponent of the Schur multiplier of a given p-group. We prove that the exponent of the Schur multiplier can be bounded by a function depending only on the exponent of a given group. As a consequence we show that the exponent of the Schur multiplier of any group of exponent four divides eight, and that this bound is best possible. The notion of the exponential rank of a p-group is introduced. We show that powerful p-groups have exponential rank either zero or one.