Parametrized homotopy theory, by J. P. May and J. Sigurdsson

We provide rigorous modern foundations for parametrized (equivariant, stable) homotopy theory in this four part monograph.

In Part I, we give preliminaries on the necessary point-set topology, on base change and other relevant functors, and on generalizations of various standard results to the context of proper actions of non-compact Lie groups.

In Part II, we give a leisurely development of the homotopy theory of ex-spaces that emphasizes several issues of independent interest. It includes much new material on the general theory of topologically enriched model categories. The essential point is to resolve problems in the homotopy theory of ex-spaces that have no nonparametrized counterparts. In contrast to previously encountered situations, model theoretic techniques are intrinsically insufficient for this purpose. Instead, a rather intricate blend of model theory and classical homotopy theory is required.

In Part III, we develop the homotopy theory of parametrized spectra. We work equivariantly and with highly structured smash products and function spectra. The treatment is based on equivariant orthogonal spectra, which are simpler for the purpose than alternative kinds of spectra. Again, there are many difficulties that have no nonparametrized counterparts and cannot be dealt with model theoretically.

In Part IV, we give a fiberwise duality theorem that allows fiberwise recognition of dualizable and invertible parametrized spectra. This allows application of the formal theory of duality in symmetric monoidal categories to the construction and analysis of transfer maps. A construction of fiberwise bundles of spectra, which are like bundles of tangents along fibers but with spectra replacing spaces as fibers, plays a central role. Using it, we obtain a simple conceptual proof of a generalized Wirthm\"uller isomorphism theorem that calculates the right adjoint to base change along an equivariant bundle with manifold fibers in terms of a shift of the left adjoint. Due to the generality of our bundle theoretic context, the Adams isomorphism theorem relating orbit and fixed point spectra is a direct consequence.

J. P. May <>
J. Sigurdsson <>