HOPF ALGEBRA STRUCTURES AND TENSOR PRODUCTS FOR GROUP ALGEBRAS
JON F. CARLSON AND SRIKANTH B. IYENGAR
Abstract. The modular group algebra of an elementary abelian p-group is iso-
morphic to the restricted enveloping algebra of commutative restricted Lie algebra.
The different ways of regarding this algebra result in different Hopf algebra struc-
tures that determine cup products on cohomology of modules. However, it is
proved in this paper that the products with elements of the polynomial subring of
the cohomology ring generated by the Bocksteins of the degree one elements are
independent of the choice of these coalgebra structures.