Syntax Definition wcdeq 3693

Description: Extend wff notation to include conditional equality. This is a technical device used in the proof that Ⅎ is the not-free predicate, and that definitions are conservative as a result.

Hypotheses

Ref	Expression
wph	wff 𝜑
vx	setvar 𝑥
vy	setvar 𝑦

Assertion

Ref	Expression
wcdeq	wff CondEq(𝑥 = 𝑦 → 𝜑)

See definition df-cdeq 3694 for more information.