Metamath Proof Explorer


Theorem wsuceq1

Description: Equality theorem for well-founded successor. (Contributed by Scott Fenton, 13-Jun-2018)

Ref Expression
Assertion wsuceq1 ⊢ R = S → wsuc R A X = wsuc S A X

Proof

Step Hyp Ref Expression
1 eqid ⊢ A = A
2 eqid ⊢ X = X
3 wsuceq123 ⊢ R = S ∧ A = A ∧ X = X → wsuc R A X = wsuc S A X
4 1 2 3 mp3an23 ⊢ R = S → wsuc R A X = wsuc S A X