P. Heath

On the group ${\cal E}(X \times Y)$ of self homotopy equivalences of a Product

Philip R. Heath

Abstract

In this talk we exhibit two interlocking sequences in order to study the group ${\cal E}(X \times Y)$ of based homotopy classes of based self homotopy equivalences of a product $X \times Y$ of topological spaces X and Y. These sequences have complementary features, and the interconnectedness facilitates computation. The sequences give new results about ${\cal E}(X \times Y)$, they also unify, generalize, and in some cases correct, existing results in the literature about this group.

New results include calculations on the group of self equivalences of a products of suspensions (with applications to a product of Moore spaces, including p localized spheres); some progress in the computation of non-simply-connected rank 2 H-spaces (posed earlier as an open problem); and a universal description of ${\cal E}(S^m \times S^n)$ for $n >m \geq 1$ as a semidirect product. This last situation includes an example that is not a semidirect product when decomposed in the only other way known.

Current applications are to the product of two spaces, but the techniques are clearly applicable to more than two. However generalizations are not entirely straight forward since some of the applications depend heavily on the fact that the product of two suspensions can be written as the mapping cone of a generalized Whitehead product. This is not available for the product of more than two suspensions.

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