Math 2.0

General topology Separation axioms Concept

Perfectly normal space

Summary

A perfectly normal space is a normal space in which every closed set is a countable intersection of open sets. Equivalently, every closed set is the zero set of a continuous real function. Every perfectly normal space is completely normal. Every metric space is perfectly normal.

Further reading

  1. Web https://en.wikipedia.org/wiki/Normal_space
About this page
TagVK3ZMD1BCP
URIm2://VK3ZMD1BCP
Kindconcept
WritingW0 stub
MSC54D15
SpecializesCompletely normal space
Changed2 November 2026

Markdown · JSON · Edit on GitHub

What this page needs for W1

  • an inventory row: the row of the inventory that the node accounts for (0 of 1)
  • a source with a locator (0 of 1)

The writing levels say how complete the text of a page is. They do not measure its truth.

What links here

Definitions