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JOURNALS // Trudy Matematicheskogo Instituta imeni V.A. Steklova // Archive

Trudy Mat. Inst. Steklova, 2024 Volume 324, Pages 24–38 (Mi tm4352)

On Tightness-Type Properties of the Space of Weakly Additive Functionals

Sh. A. Ayupovab, N. K. Mamadalievab

a V. I. Romanovskiy Institute of Mathematics, Academy of Sciences of the Republic of Uzbekistan, University st. 9, Olmazor district, Tashkent, 100174, Uzbekistan
b National University of Uzbekistan named after Mirzo Ulugbek, University st. 4, Olmazor district, Tashkent, 100174, Uzbekistan

Abstract: We study tightness-type properties such as tightness, minitightness, and local density of the space of weakly additive functionals with finite support. We also investigate some generalizations of continuous functions. Furthermore, we present an extension of the functor of weakly additive functionals with finite support to the class of strictly $\tau $-continuous mappings. We introduce two extensions of the categories $\mathrm {Comp}$ and $\mathrm {Tych}$ (of compact and Tychonoff spaces, respectively). One of the main results of the paper is that the functor $O_n$ of weakly additive functionals with finite support preserves the tightness character of infinite compact spaces. In addition, we show that the local densities of the spaces $X$ and $O_n(X)$ coincide for any infinite compact space $X$.

Keywords: tightness, minitightness, local density, normal functor, weakly additive functional.

UDC: 515.12+517

Received: June 27, 2023
Revised: July 18, 2023
Accepted: July 19, 2023

DOI: 10.4213/tm4352


 English version:
Proceedings of the Steklov Institute of Mathematics, 2024, 324, 18–32

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© Steklov Math. Inst. of RAS, 2024