The group of self-homotopy equivalences of An2-polyhedra.

Let X be a finite type An2-polyhedron, n ≥ 2. In this paper, we study the quotient group ℰ (X) / ℰ*(X), where ℰ (X) is the group of self-homotopy equivalences of X and ℰ*(X) the subgroup of self-homotopy equivalences inducing the identity on the homology groups of X. We show that not every group can be realised as ℰ (X) or ℰ (X) / ℰ *(X) for X an An2-polyhedron, n ≥ 3, and specific results are obtained for n = 2. [ABSTRACT FROM AUTHOR]