Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - add the Axiom of Infinity
Well-Founded Induction
frins2
Metamath Proof Explorer
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