Theorem frins2

Description: Founded Induction schema, using implicit substitution. (Contributed by Scott Fenton, 6-Feb-2011) (Revised by Mario Carneiro, 26-Jun-2015)

	Ref	Expression
Hypotheses	frins2.1	⊢ 𝑅 Fr 𝐴
	frins2.2	⊢ 𝑅 Se 𝐴
	frins2.3	⊢ ( 𝑦 = 𝑧 → ( 𝜑 ↔ 𝜓 ) )
	frins2.4	⊢ ( 𝑦 ∈ 𝐴 → ( ∀ 𝑧 ∈ Pred ( 𝑅 , 𝐴 , 𝑦 ) 𝜓 → 𝜑 ) )
Assertion	frins2	⊢ ( 𝑦 ∈ 𝐴 → 𝜑 )

Proof

Step	Hyp	Ref	Expression
1		frins2.1	⊢ 𝑅 Fr 𝐴
2		frins2.2	⊢ 𝑅 Se 𝐴
3		frins2.3	⊢ ( 𝑦 = 𝑧 → ( 𝜑 ↔ 𝜓 ) )
4		frins2.4	⊢ ( 𝑦 ∈ 𝐴 → ( ∀ 𝑧 ∈ Pred ( 𝑅 , 𝐴 , 𝑦 ) 𝜓 → 𝜑 ) )
5		nfv	⊢ Ⅎ 𝑦 𝜓
6	1 2 5 3 4	frins2f	⊢ ( 𝑦 ∈ 𝐴 → 𝜑 )