Abstract
Let G be a finite p-group. Let and
respectively denote the group of all absolute central and
-automorphisms of G. We give necessary and sufficient conditions for a finite non-abelian p-group G such that
and as a consequence, we prove that for a finite non-abelian p-group G of order up to p4,
if and only if
where L(G) denotes the absolute center of G.