1999/12/27 by Lowell Abrams, Abrams, Lowell, Charles A. Weibel +2
Computer Science · Mathematics · #16E40 (Primary) #16W30 (Secondary) #Advanced Algebra and Logic #Algebraic Topology (math.AT) #FOS: Mathematics #Rings and Algebras (math.RA) #Rings, Modules, and Algebras #math.AT #math.RA #msc:16E40 #msc:16W30
paper · pdf · doi:10.48550/arxiv.math/9912211
16 pages, LaTeX
arxiv created 1999/12/27 · openalex publication_date 1999/12/27 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Let C be a coalgebra over a field k and A its dual algebra. The category of C-comodules is equivalent to a category of A-modules. We use this to interpret the cotensor product M \square N of two comodules in terms of the appropriate Hochschild cohomology of the A-bimodule M ⊗ N, when A is finite-dimensional, profinite, graded or differential-graded. The main applications are to Galois cohomology, comodules over the Steenrod algebra, and the homology of induced fibrations.