Graded identities of Mn(E) and their generalizations over infinite fields

Abstract

Let G be a group and F an infinite field. Assume that A is a finite dimensional F-algebra with an elementary G-grading. In this paper, we study the graded identities satisfied by the tensor product grading on the F-algebra A⊗C, where C is an H-graded colour β-commutative algebra. More precisely, under a technical condition, we provide a basis for the TG-ideal of graded polynomial identities of A⊗C, up to graded monomial identities. Furthermore, the F-algebra of upper block-triangular matrices UT(d1,…,dn), as well as the matrix algebra Mn(F), with an elementary grading such that the neutral component corresponds to its diagonal, are studied. As a consequence of our results, a basis for the graded identities, up to graded monomial identities of degrees ≤2d−1, for Md(E) and Mq(F)⊗UT(d1,…,dn), with a tensor product grading, is exhibited. In this latter case, d=d1+…+dn. Here E denotes the infinite dimensional Grassmann algebra with its natural Z2-grading, and the grading on Mq(F) is Pauli grading. The results presented in this paper generalize results from [14] and from other papers which were obtained for fields of characteristic zero.