English

Positivstellensatz\"e for noncommutative rational expressions

Functional Analysis 2017-03-22 v1 Rings and Algebras

Abstract

We derive some Positivstellensatz\"e for noncommutative rational expressions from the Positivstellensatz\"e for noncommutative polynomials. Specifically, we show that if a noncommutative rational expression is positive on a polynomially convex set, then there is an algebraic certificate witnessing that fact. As in the case of noncommutative polynomials, our results are nicer when we additionally assume positivity on a convex set-- that is, we obtain a so-called "perfect Positivstellensatz" on convex sets.

Keywords

Cite

@article{arxiv.1703.06951,
  title  = {Positivstellensatz\"e for noncommutative rational expressions},
  author = {J. E. Pascoe},
  journal= {arXiv preprint arXiv:1703.06951},
  year   = {2017}
}

Comments

6 pages

R2 v1 2026-06-22T18:51:42.541Z