Journal of Algebra 222, 471᎐484Ž. 1999 doi:10.1006rjabr.1999.8016, available online at http:rrwww.idealibrary.com on Involution Codimensions of Finite Dimensional Algebras and Exponential Growth A. Giambruno View metadata, citation and similar papers at core.ac.uk brought to you by CORE Dipartimento di Matematica e Applicazioni, Uni¨ersitaÁ di Palermo, 90123 Palermo, Italy provided by Elsevier - Publisher Connector E-mail:
[email protected] and M. Zaicev Department of Algebra, Faculty of Mathematics and Mechanics, Moscow State Uni¨ersity, Moscow, 119899 Russia E-mail:
[email protected] Communicated by Susan Montgomery Received March 26, 1999 Let F be a field of characteristic zero and let A be a finite dimensional algebra with involution ) over F. We study the asymptotic behavior of the sequence of n ) ) ) s ) -codimensions cAnnŽ., of A and we show that ExpŽ.A, lim ªϱ 'cAnŽ., exists and is an integer. We give an explicit way for computing ExpŽ.A, ) and as a consequence we obtain the following characterization of )-simple algebras: A is ) ) s ᮊ -simple if and only if ExpŽ.A, dim F A. 2000 Academic Press 1. INTRODUCTION The purpose of this paper is to determine for any finite dimensional algebra with involution the exponential growth of its sequence of )-codi- mensions in characteristic zero. Let F be a field of characteristic zero and let A be an F-algebra with ) ) involution . Let VnŽ.be the space of multilinear polynomials in the UU ) variables x11, x ,..., xnn, x and let WA nŽ., be the subspace of multilin- ) ) ear -polynomial identities of A; then the codimension of WAnŽ., is ) cAnŽ., , the nth codimension of A.