The hit problem for a cohomology module over the Steenrod algebra A asks for a
minimal set of A–generators for the module. In this paper we consider the
symmetric algebras over the field Fp, for p an arbitrary prime, and treat
the equivalent problem of determining the set of A*–primitive elements in
their duals. We produce a method for generating new primitives from known
ones via a new action of the Kudo–Araki–May algebra K, and consider the
K–module structure of the primitives, which form a sub K–algebra of the dual
of the infinite symmetric algebra. Our examples show that the K–action
on the primitives is not free. Our new action encompasses, on the finite
symmetric algebras, the operators introduced by Kameko for studying the hit
problem.