Group cohomology without groups

Abstract

This talk uses the Dickson invariants (about 1911) and some major theorems of Quillen (about 1971) to find the canonical classes in the cohomology of finite groups.  Canonical classes surfaced in the geometry of manifolds decades ago, but those in modular representation theory are only partly analogous.  Associated spectral sequences then emerge.  The relevance to block algebras (prodands of modular group algebras) may then be discussed.  In fact light is thrown upon the homological algebra of block algebras.   My paper published in the Journal of Algebra over 40 years ago now needs a sequel!