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 ลฝ . ลฝ . )-codimensions c A, ) of A and we show that Exp A, ) s lim c A, ) ' ลฝ . n n ยช ฯฑ n ลฝ . exists and is an integer. We give an expli
Exponential Codimension Growth of PI Algebras: An Exact Estimate
โ Scribed by A Giambruno; M Zaicev
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 235 KB
- Volume
- 142
- Category
- Article
- ISSN
- 0001-8708
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โฆ Synopsis
Let A be an associative PI-algebra over a field F of characteristic zero. By studying the exponential behavior of the sequence of codimensions [c n (A)] of A, we prove that Inv(A)=lim n ร n c n (A) always exists and is an integer. We also give an explicit way for computing such integer: let B be a finite dimensional Z 2 -graded algebra whose Grassmann envelope G(B) satisfies the same identities of A; then Inv(A)=Inv(G(B))=dim C (0) +dim C (1) where C (0) +C (1) is a suitable Z 2 -graded semisimple subalgebra of B.
๐ SIMILAR VOLUMES
By the Giambruno-Zaicev theorem for associative p.i. algebras, the exponential rate of growth of the codimensions of such a p.i. algebra is always a positive integer. Here we calculate that integer for various generic p.i. algebras which are given by a single identity. These include Capelli-type id