English

Weighted Orlicz $*$-algebras on locally elliptic groups

Functional Analysis 2026-03-16 v2 Group Theory Operator Algebras Representation Theory

Abstract

Let GG be a locally elliptic group, (Φ,Ψ)(\Phi,\Psi) a complementary pair of Young functions, and ω:G[1,)\omega: G \rightarrow [1,\infty) a weight function on GG such that the weighted Orlicz space LΦ(G,ω)L^\Phi(G,\omega) is a Banach *-algebra when equipped with the convolution product and involution f(x):=f(x1)f^*(x):=\overline{f(x^{-1})} (fLΦ(G,ω)f \in L^\Phi(G,\omega)). Such a weight always exists on GG and we call it an LΦL^\Phi-weight. We assume that 1/ωLΨ(G)1/\omega \in L^\Psi(G) so that LΦ(G,ω)L1(G)L^\Phi(G,\omega) \subseteq L^1(G). This paper studies the spectral theory and primitive ideal structure of LΦ(G,ω)L^\Phi(G,\omega). In particular, we focus on studying the Hermitian, Wiener and *-regularity properties on this algebra, along with some related questions on spectral synthesis. It is shown that LΦ(G,ω)L^\Phi(G,\omega) is always quasi-Hermitian, weakly-Wiener and *-regular. Thus, if LΦ(G,ω)L^\Phi(G,\omega) is Hermitian, then it is also Wiener. Although, in general, LΦ(G,ω)L^\Phi(G,\omega) is not always Hermitian, it is known that Hermitianness of L1(G)L^1(G) implies Hermitianness of LΦ(G,ω)L^\Phi(G,\omega) if ω\omega is sub-additive. We give numerous examples of locally elliptic groups GG for which L1(G)L^1(G) is Hermitian and sub-additive LΦL^\Phi-weights on these groups. In the weighted L1L^1 case, even stronger Hermitianness results are formulated.

Keywords

Cite

@article{arxiv.2503.20735,
  title  = {Weighted Orlicz $*$-algebras on locally elliptic groups},
  author = {Max Carter},
  journal= {arXiv preprint arXiv:2503.20735},
  year   = {2026}
}

Comments

33 pages. Some minor changes have been made to the exposition. Accepted for publication in Studia Mathematica