Algebraic infinite delooping and derived destabilization

Geoffrey Powell

Published 2017-01-23Version 1

Working over the prime field of characteristic two, consequences of the Koszul duality between the Steenrod algebra and the big Dyer-Lashof algebra are studied, with an emphasis on the interplay between instability for the Steenrod algebra action and that for the Dyer-Lashof operations. The central algebraic framework is the category of length-graded modules over the Steenrod algebra equipped with an unstable action of the Dyer-Lashof algebra, with compatibility via the Nishida relations. A first ingredient is a functor defined on modules over the Steenrod algebra that arose in the work of Kuhn and McCarty on the homology of infinite loop spaces. This functor is given in terms of derived functors of destabilization from the category of modules over the Steenrod algebra to unstable modules, enriched by taking into account the action of Dyer-Lashof operations. A second ingredient is the derived functors of the Dyer-Lashof indecomposables functor to length-graded modules over the Steenrod algebra. These are related to functors used by Miller in his study of a spectral sequence to calculate the homology of an infinite delooping. An important fact is that these functors can be calculated as the homology of an explicit Koszul complex with terms expressed as certain Steinberg functors. The latter are quadratic dual to the more familiar Singer functors. By exploiting the explicit complex built from the Singer functors which calculates the derived functors of destabilization, Koszul duality leads to an algebraic infinite delooping spectral sequence. This is conceptually similar to Miller's spectral sequence, but there seems to be no direct relationship. The spectral sequence sheds light on the relationship between unstable modules over the Steenrod algebra and all modules.