Mod 3 homotopy associative H-spaces which are products of spheres
It is not known if a finite p-local A(p)-space always has the homotopy type of a topological group for odd p. This is established for the prime 3 for 3-regular finite H-space, where an A(3)-space is a homotopy associative H-space. The proof in this particular case is far from straightforward and uses unstable tertiary cohomology operations, ladder Toda brackets and results from earlier papers on the same topic. (An alternative K-theoretic proof was later produced by N. Iwase.)
scientific article; zbMATH DE number 4076061