Metamath Proof Explorer


Theorem frins2

Description: Well-Founded Induction schema, using implicit substitution. (Contributed by Scott Fenton, 8-Feb-2011) (Revised by Mario Carneiro, 26-Jun-2015)

Ref Expression
Hypotheses frins2.1 ⊢ y ∈ A → ∀ z ∈ Pred R A y ψ → φ
frins2.3 ⊢ y = z → φ ↔ ψ
Assertion frins2 ⊢ R Fr A ∧ R Se A → ∀ y ∈ A φ

Proof

Step Hyp Ref Expression
1 frins2.1 ⊢ y ∈ A → ∀ z ∈ Pred R A y ψ → φ
2 frins2.3 ⊢ y = z → φ ↔ ψ
3 nfv ⊢ Ⅎ y ψ
4 1 3 2 frins2f ⊢ R Fr A ∧ R Se A → ∀ y ∈ A φ