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