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ЖУРНАЛЫ // Eurasian Mathematical Journal // Архив

Eurasian Math. J., 2024, том 15, номер 1, страницы 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

Аннотация: 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 $L^p(\mathcal{H})\times L^q(\mathcal{H})$.

Ключевые слова и фразы: locally compact hypergroup, center of hypergroups, porosity, $\sigma$-lower porosity, spaceability, Lebesgue spaces, Hilbert spaces, convolution.

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

Поступила в редакцию: 10.12.2022
Принята в печать: 05.01.2024

Язык публикации: английский

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



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