# Sigma-compact space

From Topospaces

This article defines a property of topological spaces: a property that can be evaluated to true/false for any topological space|View a complete list of properties of topological spaces

This is a variation of compactness. View other variations of compactness

## Contents

## Definition

### Symbol-free definition

A topological space is said to be **sigma-compact** or -compact if it has a countable collection of compact subsets such that the union of their interiors is the whole space.