Weighted homomorphisms on the $p$-analog of the Fourier-Stieltjes algebra induced by piecewise affine maps

TL;DR

This paper investigates the $p$-complete boundedness of weighted homomorphisms on the $p$-analog of Fourier-Stieltjes algebras, focusing on maps induced by piecewise affine functions and their properties.

Contribution

It establishes conditions under which these homomorphisms are $p$-completely contractive or bounded, extending the understanding of their structure and behavior.

Findings

Homomorphisms induced by affine maps are $p$-completely contractive.

Piecewise affine maps induce $p$-completely bounded homomorphisms.

Relations between $B_p(G/N)$ and subalgebras of $B_p(G)$ are characterized.

Abstract

In this paper, for $p\in(1,\infty)$ we study $p$-complete boundedness of weighted homomorphisms on the $p$-analog of the Fourier-Stieltjes algebras, $B_p(G)$, based on the $p$-operator space structure defined by the authors. Here, for a locally compact group $G$, the space $B_p(G)$ stands for Runde's definition of the $p$-analog of the Fourier-Stieltjes algebra and the implemented $p$-operator space structure is come from the duality between $B_p(G)$ and the algebra of universal $p$-pseudofunctions, $UPF_p(G)$. It is established that the homomorphism $\Phi_\alpha:B_p(G)\to B_p(H)$, defined by $\Phi(u)=u\circ\alpha$ on $Y$ and zero otherwise, is $p$-completely contractive when the continuous and proper map $\alpha :Y\subseteq H\to G$ is affine, and it is $p$-completely bounded whenever $\alpha$ is piecewise affine map. Moreover, we assume that $Y$ belongs to the coset ring generated by open and amenable subgroups of $H$. To obtain the result, by utilizing the properties of $QSL_p$-spaces and representations on them, the relation between $B_p(G/N)$ and a closed subalgebra of $B_p(G)$ is shown, where $N$ is a closed normal subgroup of $G$. Additionally, $p$-complete boundedness of several well-known maps on such algebras are obtained.