English

Twisted convolution algebras with coefficients in a differential subalgebra

Operator Algebras 2025-03-17 v3

Abstract

Let (G,α,ω,B)({\sf G},\alpha, \omega,\mathfrak B) be a measurable twisted action of the locally compact group G{\sf G} on a Banach ^*-algebra B\mathfrak B and A\mathfrak A a differential Banach ^*-subalgebra of B\mathfrak B, which is stable under said action. We observe that Lα,ω1(G,A)L^1_{\alpha,\omega}({\sf G},\mathfrak A) is a differential subalgebra of Lα,ω1(G,B)L^1_{\alpha,\omega}({\sf G},\mathfrak B). We use this fact to provide new examples of groups with symmetric Banach ^*-algebras. In particular, we prove that discrete rigidly symmetric extensions of compact groups are symmetric or that semidirect products KH{\sf K}\rtimes{\sf H}, with H{\sf H} symmetric and K{\sf K} compact, are symmetric.

Keywords

Cite

@article{arxiv.2309.08846,
  title  = {Twisted convolution algebras with coefficients in a differential subalgebra},
  author = {Felipe I. Flores},
  journal= {arXiv preprint arXiv:2309.08846},
  year   = {2025}
}

Comments

9 pages. Some typos are fixed. The title is changed

R2 v1 2026-06-28T12:23:17.721Z