ILE Home Intuitionistic Logic Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  ILE Home  >  Th. List  >  df-cdeq GIF version

Definition df-cdeq 2800
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 CondEq𝑥𝑦𝜑. 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 = 𝑦𝜑) ↔ (𝑥 = 𝑦𝜑))

Detailed syntax breakdown of Definition df-cdeq
StepHypRef Expression
1 wph . . 3 wff 𝜑
2 vx . . 3 setvar 𝑥
3 vy . . 3 setvar 𝑦
41, 2, 3wcdeq 2799 . 2 wff CondEq(𝑥 = 𝑦𝜑)
52, 3weq 1433 . . 3 wff 𝑥 = 𝑦
65, 1wi 4 . 2 wff (𝑥 = 𝑦𝜑)
74, 6wb 103 1 wff (CondEq(𝑥 = 𝑦𝜑) ↔ (𝑥 = 𝑦𝜑))
Colors of variables: wff set class
This definition is referenced by:  cdeqi  2801  cdeqri  2802  bdcdeq  10788
  Copyright terms: Public domain W3C validator