Definition:Class Intersection

Definition
Let $A$ and $B$ be two classes.

The (class) intersection $A \cap B$ of $A$ and $B$ is defined as the class of all sets $x$ such that $x \in A$ and $x \in B$:


 * $x \in A \cap B \iff x \in A \land x \in B$

or:
 * $A \cap B = \set {x: x \in A \land x \in B}$

Also see

 * Definition:Set Intersection, the usual presentation of this concept in set theory


 * Definition:Class Union