# Cover

From Maths

## Definition

An arbitrary family of sets, [ilmath]\{S_\alpha\}_{\alpha\in I}[/ilmath] is said to *cover* another set, [ilmath]X[/ilmath] if^{[1]}:

- [math]X\subseteq\bigcup_{\alpha\in I}S_\alpha[/math], that is to say that:
- [ilmath]X[/ilmath] is contained in the union of the members of the family.