Definition df-cdeq 3419

Description: Define conditional equality. All the notation to the left of the <-> is fake; the parentheses and arrows are all part of the notation, which could equally well be written CondEq x y ph. On the right side is the actual implication arrow. The reason for this definition is to "flatten" the structure on the right side (whose tree structure is something like (wi (wceq (cv vx) (cv vy)) wph) ) into just (wcdeq vx vy wph). (Contributed by Mario Carneiro, 11-Aug-2016.)

Assertion

Ref	Expression
df-cdeq	|- (CondEq ( x = y -> ph ) <-> ( x = y -> ph ) )

Detailed syntax breakdown of Definition df-cdeq

Step	Hyp	Ref	Expression
1		wph	. . 3 wff ph
2		vx	. . 3 setvar x
3		vy	. . 3 setvar y
4	1, 2, 3	wcdeq 3418	. 2 wff CondEq ( x = y -> ph )
5	2, 3	weq 1874	. . 3 wff x = y
6	5, 1	wi 4	. 2 wff ( x = y -> ph )
7	4, 6	wb 196	1 wff (CondEq ( x = y -> ph ) <-> ( x = y -> ph ) )

This definition is referenced by:  cdeqi  3420  cdeqri  3421