Theorem cbv3v 1724

Description: Rule used to change bound variables, using implicit substitution. Version of cbv3 1722 with a disjoint variable condition. (Contributed by NM, 5-Aug-1993.) (Revised by BJ, 31-May-2019.)

Hypotheses

Ref	Expression
cbv3v.nf1	⊢ Ⅎ𝑦𝜑
cbv3v.nf2	⊢ Ⅎ𝑥𝜓
cbv3v.1	⊢ (𝑥 = 𝑦 → (𝜑 → 𝜓))

Assertion

Ref	Expression
cbv3v	⊢ (∀𝑥𝜑 → ∀𝑦𝜓)

Distinct variable group:   𝑥,𝑦

Allowed substitution hints:   𝜑(𝑥,𝑦)   𝜓(𝑥,𝑦)

Proof of Theorem cbv3v

Step	Hyp	Ref	Expression
1		cbv3v.nf1	. 2 ⊢ Ⅎ𝑦𝜑
2		cbv3v.nf2	. 2 ⊢ Ⅎ𝑥𝜓
3		cbv3v.1	. 2 ⊢ (𝑥 = 𝑦 → (𝜑 → 𝜓))
4	1, 2, 3	cbv3 1722	1 ⊢ (∀𝑥𝜑 → ∀𝑦𝜓)

Syntax hints:   → wi 4  ∀wal 1333  Ⅎwnf 1440

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-5 1427  ax-7 1428  ax-gen 1429  ax-ie1 1473  ax-ie2 1474  ax-4 1490  ax-i9 1510  ax-ial 1514

This theorem depends on definitions:  df-bi 116  df-nf 1441

This theorem is referenced by:  cbv1v  1727  cbvalv1  1731