RUS  ENG
Full version
JOURNALS // Vestnik Moskovskogo Universiteta. Seriya 1. Matematika. Mekhanika // Archive

Vestnik Moskov. Univ. Ser. 1. Mat. Mekh., 2017 Number 5, Pages 48–51 (Mi vmumm95)

This article is cited in 3 papers

Short notes

The weak form of normality

A. P. Kombarov

Lomonosov Moscow State University, Faculty of Mechanics and Mathematics

Abstract: A topological space is said to be paranormal if every countable discrete collection of closed sets $\{D_n: n<\omega\}$ can be expanded to a locally finite collection of open sets $\{U_n: n<\omega\}$, i.e., $D_n\subset U_n$ and $D_m\cap U_n\not=\emptyset$ if and only if $D_m=D_n$. It is proved that if $\mathcal{F}:$ Comp $ \to$ Comp is a normal functor of degree $\geq 3$ and the compact space ${\mathcal{F}}(X)$ is hereditarily paranormal, then the compact space $X$ is metrizable.

Key words: normal functor, compact space, hereditarily paranormality, metrizability.

UDC: 515.12

Received: 20.04.2016


 English version:
Moscow University Mathematics Bulletin, Moscow University Måchanics Bulletin, 2017, 72:5, 203–205

Bibliographic databases:


© Steklov Math. Inst. of RAS, 2026