Published online by Cambridge University Press: 24 October 2008
Let us denote the group of based homotopy classes of seif-homotopy equivalences of a space X by E(X). We consider E0(X), the subgroup of E(X) consisting of elements which induce the identity map on homology. Dror and Zabrodsky have shown that E0(X) and the subgroup E#(X) consisting of elements inducing the identity on homotopy are both nilpotent groups for finite-dimensional nilpotent spaces, or finite-dimensional spaces respectively ([4], theorem D, theorem A). The theory of localization for nilpotent groups has been developed by several authors (see [8]). The aim of this paper is to prove the following theorem. The corresponding result for E#(X) is obtained in [9], theorem 0·1.