English

Clarkson-McCarthy inequality on a locally compact group

Functional Analysis 2025-02-27 v1

Abstract

Let GG be a locally compact group, μ\mu its Haar measure, G^\hat G its Pontryagin dual and ν\nu the dual measure. For any AθL1(G;Cp)L2(G;Cp)A_\theta\in L^1(G;\mathcal C_p)\cap L^2(G;\mathcal C_p), (Cp\mathcal C_p is Schatten ideal), and 1<p21<p\le2 we prove G^GAθξ(θ)dμ(θ)pqdν(ξ)(GAθppdμ(θ))q/p,\int_{\hat G}\left\|\int_GA_\theta\overline{\xi(\theta)}\,\mathrm d\mu(\theta)\right\|_p^q\,\mathrm d\nu(\xi)\le \left(\int_G\|A_\theta\|_p^p\,\mathrm d\mu(\theta)\right)^{q/p}, where q=p/(p1)q=p/(p-1). This appears to be a generalization of some earlier obtained inequalities, including Clarkson-McCarthy inequalities (in the case G=Z2G=\mathbf Z_2), and Hausdorff-Young inequality. Some corollaries are also given.

Cite

@article{arxiv.2502.19188,
  title  = {Clarkson-McCarthy inequality on a locally compact group},
  author = {Dragoljub J. Kečkić and Zlatko Lazović},
  journal= {arXiv preprint arXiv:2502.19188},
  year   = {2025}
}

Comments

11 pages

R2 v1 2026-06-28T21:58:46.531Z