Union

From Maths
Jump to: navigation, search
(Unknown grade)
This page is a stub
This page is a stub, so it contains little or minimal information and is on a to-do list for being expanded.
(Unknown grade)
This page requires references, it is on a to-do list for being expanded with them.
Please note that this does not mean the content is unreliable, it just means that the author of the page doesn't have a book to hand, or remember the book to find it, which would have been a suitable reference.

Definition

Given a collection of sets [ilmath]\{S_\alpha\}_{\alpha\in A} [/ilmath] their union is:

  • [math]\bigcup_{\alpha\in A}S_\alpha[/math] with the characteristic property that:
    • [math]x\in\bigcup_{\alpha\in A}S_\alpha\iff\exists\beta\in A[x\in S_\beta][/math]

Immediate results

References