RUS  ENG
Full version
JOURNALS // Vestnik Tomskogo Gosudarstvennogo Universiteta. Matematika i Mekhanika // Archive

Vestn. Tomsk. Gos. Univ. Mat. Mekh., 2024 Number 89, Pages 32–50 (Mi vtgu1081)

MATHEMATICS

Subspaces dimensional properties that are boundary sets of the probability measures space, defined in an infinite compactum $X$

T. F. Zhuraeva, Q. R. Zhuvonovb

a Tashkent State Pedagogical University named after Nizami, Tashkent, Uzbekistan
b National Research University "Tashkent Institute of Irrigation and Agricultural Mechanization Engineers", Tashkent, Uzbekistan

Abstract: In this note, we consider dimensional properties of the subspace of probability measure spaces $P(X)$ for which transfinite dimensional functions $ind$, $Ind$ и $\mathrm{dim}$ are defined. It is shown that countability of a compact set $X$ is equivalent to the existence of dimensions $ind\,P_\omega(X)$, $Ind\,P_\omega(X)$, $\mathrm{dim}\,P_\omega(X)$, $ind\,P_f(X)$, $Ind\,P_f(X)$ and $\mathrm{dim}\,P_f(X)$ for the subspaces $P_\omega(X)$, $P_f(X)$, $P_n(X)$ respectively. It is also noted that for any compact $C$-space of the subspaces $P_n(X)$, $P_\omega(X)$, $P_f(X)$ the space $P(x)$ are compact $C$-spaces. If for an infinite compact set $X$ the subspace $P_\omega(X)$ contains the Hilbert cube $\mathcal{Q}$, then there exists a number $n\in N$, $n>1$, such that $X^n \sigma^{n-1}$ contains the Hilbert cube $\mathcal{Q}$. Further, for an infinite compact set $X$, a number of subspaces $Y$ of the compact set $P (x)$ which are $\mathcal{Q}$-, $\ell_2$-, $\ell_2^f$- and $\Sigma$-manifolds are identified. In particular, for a proper closed subset $A\subset X$, the subspaces $S_p(A)$ are $\ell_2$-manifolds; for any $n \in N$, $n>$1, $P(X) \setminus P_n(X)$ are $\mathcal{Q}$-manifolds; for any proper everywhere dense countable subspace $A\subset X$, the subspace $P_\omega(A$) is the boundary set of the compact set $P (x)$. If $P_\omega(X)$ contains the Hilbert cube $\mathcal{Q}$, then the subspace $P_\omega$(X) is homeomorphic to the space $\Sigma$.
It is considered in which cases everywhere dense subsets $A$ of the spaces $P(X)$ defined in an infinite compactum $X$ are its boundary set. It is also shown which everywhere dense subsets $A\subset P(X)$ and $B\subset P(Y)$ for infinite compact sets $X$ and $Y$ of the spaces $P(X)$ and $P(Y)$, respectively, are at the same time mutually homeomorphic.

Keywords: probability measures, dimensions $ind$, $Ind$, $\mathrm{dim}$, boundary sets.

UDC: 515.12

MSC: 54B15, 54B30, 54B35, 54C05, 54C15, 54C60, 54O30

Received: 01.07.2020
Accepted: June 3, 2024

DOI: 10.17223/19988621/89/3



© Steklov Math. Inst. of RAS, 2024