# Category:Doubleton Classes

This category contains results about Doubleton Classes.

Let $a$ and $b$ be sets.

The class $\set {a, b}$ is a doubleton (class).

It is defined as the class of all $x$ such that $x = a$ or $x = b$:

$\set {a, b} = \set {x: x = a \lor x = b: a \ne b}$

## Pages in category "Doubleton Classes"

The following 4 pages are in this category, out of 4 total.