Equivariant Total Ring of Fractions and Factoriality of Rings Generated by Semi-Invariants

Mitsuyasu Hashimoto

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Utilizing this machinery, we give some new criteria for factoriality (unique factorization domain property) of (semi-)invariant subrings under the action of affine algebraic groups, generalizing a result of Popov. We also prove some variations of classical results on factoriality of (semi-)invariant subrings. Some results over an algebraically closed base field are generalized to those over an arbitrary base field.

Let F be an affine flat group scheme over a commutative ring R, and S an F-algebra (an R-algebra on which F acts). We define an equivariant analogue Q F(S) of the total ring of fractions Q(S) of S. It is the largest F-algebra T such that S ⊂ T ⊂ Q(S), and S is an F-subalgebra of T. We study some basic properties.

Original languageEnglish
Pages (from-to)1524-1562
Number of pages39
JournalCommunications in Algebra
Issue number4
Publication statusPublished - Apr 3 2015


  • Character group
  • Invariant subring
  • UFD

ASJC Scopus subject areas

  • Algebra and Number Theory


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