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arXiv · 2607.23028

Adherence Semigroups and Density Finite-Sums Configurations

Song Shao·Hui Xu
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Abstract

In this paper, we use the adherence semigroup to describe finite-sums configurations in topological dynamical systems. We establish a correspondence between exact finite sumsets and powers of adherence elements. As applications, we give dynamical formulations of density finite-sums results, characterize total minimality through the density of adherence-power orbits, and give a positive answer to the ultrafilter question in [Question~8.9, 6]. We also characterize the sets that belong to the common sum of two commuting nonprincipal ultrafilters.

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Song Shao, Hui Xu. 2026-07-25. Adherence Semigroups and Density Finite-Sums Configurations. https://arxiv.org/abs/2607.23028

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