RUS  ENG
Full version
JOURNALS // Eurasian Mathematical Journal // Archive

Eurasian Math. J., 2024 Volume 15, Number 1, Pages 75–90 (Mi emj494)

Porosity in the context of hypergroups

S. M. Tabatabaie, A. R. Bagheri Salec, H. R. J. Allami

Department of Mathematics, University of Qom, Qom, Iran

Abstract: In this paper we show that the set of all elements $g\in L^p(\mathcal{H})$ for which $(|g|*|g|)(x)<\infty$ for a center element $x\in B$, is $\sigma$-$c$-lower porous, where $p > 2$, $\mathcal{H}$ is a non-compact unimodular hypergroup and $B$ is some special symmetric compact neighborhood of the identity element. As an application, we give some new equivalent condition for the finiteness of a discrete Hermitian hypergroup. Moreover, we give some sufficient conditions for the set of all pairs $(f, g)$ in $L^p(\mathcal{H})\times L^q(\mathcal{H})$ for which for a center element $x\in B$, $(|f|*|g|)(x)<\infty$, is a $\sigma$-$c$-lower porous, where $p, q > 1$ with $\frac1p+\frac1q<1$. Also, we show that the complement of this set is spaceable in $L^p(\mathcal{H})\times L^q(\mathcal{H})$.

Keywords and phrases: locally compact hypergroup, center of hypergroups, porosity, $\sigma$-lower porosity, spaceability, Lebesgue spaces, Hilbert spaces, convolution.

MSC: 43A62, 46E30, 43A15, 54E52, 42A85, 44A35

Received: 10.12.2022
Accepted: 05.01.2024

Language: English

DOI: 10.32523/2077-9879-2024-15-1-75-90



© Steklov Math. Inst. of RAS, 2024