Trace codimensions of algebras and their exponential growth

Abstract

The trace codimensions give a quantitative description of the identities satisfied by an algebra with trace.Here we study the asymptotic behaviour of the sequence of trace codimensions c tr n (A) and of pure trace codimensions c ptr n (A) of a finite dimensional algebra A over a field of characteristic zero. We find an upper and lower bound of both codimensions and as a consequence we get that the limits limn→∞ n c tr n (A) and limn→∞ n c ptr n (A) always exist and are integers. This result gives a positive answer to a conjecture of Amitsur in this setting. Finally we characterize the varieties of algebras whose exponential growth is bounded by 2.