Syntax Definition cab 2156

Description: Introduce the class builder or class abstraction notation ("the class of sets x such that ph is true"). Our class variables A, B, etc. range over class builders (sometimes implicitly). Note that a setvar variable can be expressed as a class builder per Theorem cvjust 2165, justifying the assignment of setvar variables to class variables via the use of cv 1347.

Hypotheses

Ref	Expression
wph	wff ph
vx	setvar x

Assertion

Ref	Expression
cab	class { x | ph }

See definition df-clab 2157 for more information.