English

Essential dimension of representations of algebras

Algebraic Geometry 2020-02-24 v3 Representation Theory

Abstract

Let kk be a field, AA a finitely generated associative kk-algebra and RepA[n]\operatorname{Rep}_A[n] the functor FieldskSets\operatorname{Fields}_k\to \operatorname{Sets}, which sends a field KK containing kk to the set of isomorphism classes of representations of AKA_K of dimension at most nn. We study the asymptotic behavior of the essential dimension of this functor, i.e., the function rA(n):=edk(RepA[n])r_A(n) := \operatorname{ed}_k(\operatorname{Rep}_A[n]), as nn\to\infty. In particular, we show that the rate of growth of rA(n)r_A(n) determines the representation type of AA. That is, rA(n)r_A(n) is bounded from above if AA is of finite representation type, grows linearly if AA is of tame representation type and grows quadratically if A is of wild representation type. Moreover, rA(n)r_A(n) is a finer invariant of A, which allows us to distinguish among algebras of the same representation type.

Keywords

Cite

@article{arxiv.1804.00642,
  title  = {Essential dimension of representations of algebras},
  author = {Federico Scavia},
  journal= {arXiv preprint arXiv:1804.00642},
  year   = {2020}
}

Comments

Accepted version