Let p be any prime, and let B(p) be the algebra of operations on the cohomology ring of any cocommutative Fp-Hopf algebra. In this paper we show that when
p is odd (and unlike the p = 2 case), B(p) cannot become an object in the Singer
category of Fp-algebras with coproducts, if we require that coproducts act on the
generators of B(p) coherently with their nature of cohomology operations.

• A note on the algebra of operations for Hopf cohomology at odd primes