6533b7d2fe1ef96bd125ec18

RESEARCH PRODUCT

Polynomial identities on superalgebras and exponential growth

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Abstract Let A be a finitely generated superalgebra over a field F of characteristic 0. To the graded polynomial identities of A one associates a numerical sequence {cnsup(A)}n⩾1 called the sequence of graded codimensions of A. In case A satisfies an ordinary polynomial identity, such sequence is exponentially bounded and we capture its exponential growth by proving that for any such algebra lim n→∞ c n sup (A) n exists and is a non-negative integer; we denote such integer by supexp(A) and we give an effective way for computing it. As an application, we construct eight superalgebras Ai, i=1,…,8, characterizing the identities of any finitely generated superalgebra A with supexp(A)>2 in the following way: supexp(A)>2 if and only if Idsup(A)⊆Idsup(Ai) for some i∈{1,…,8}, where Idsup(B) is the ideal of graded identities of the algebra B. We also compare the superexponent and the exponent (see A. Giambruno, M. Zaicev, Adv. Math. 140 (1998) 145–155) of any finitely generated superalgebra.