Theorem cbv1v 2370

Description: Rule used to change bound variables, using implicit substitution. Version of cbv1 2436 with a disjoint variable condition, which does not require ax-13 2406. (Contributed by NM, 5-Aug-1993.) (Revised by BJ, 16-Jun-2019.)

Hypotheses

Ref	Expression
cbv1v.1	⊢ Ⅎ𝑥𝜑
cbv1v.2	⊢ Ⅎ𝑦𝜑
cbv1v.3	⊢ (𝜑 → Ⅎ𝑦𝜓)
cbv1v.4	⊢ (𝜑 → Ⅎ𝑥𝜒)
cbv1v.5	⊢ (𝜑 → (𝑥 = 𝑦 → (𝜓 → 𝜒)))

Assertion

Ref	Expression
cbv1v	⊢ (𝜑 → (∀𝑥𝜓 → ∀𝑦𝜒))

Distinct variable group:   𝑥,𝑦

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

Proof of Theorem cbv1v

Step	Hyp	Ref	Expression
1		cbv1v.2	. . . . 5 ⊢ Ⅎ𝑦𝜑
2		cbv1v.3	. . . . 5 ⊢ (𝜑 → Ⅎ𝑦𝜓)
3	1, 2	nfim1 2238	. . . 4 ⊢ Ⅎ𝑦(𝜑 → 𝜓)
4		cbv1v.1	. . . . 5 ⊢ Ⅎ𝑥𝜑
5		cbv1v.4	. . . . 5 ⊢ (𝜑 → Ⅎ𝑥𝜒)
6	4, 5	nfim1 2238	. . . 4 ⊢ Ⅎ𝑥(𝜑 → 𝜒)
7		cbv1v.5	. . . . . 6 ⊢ (𝜑 → (𝑥 = 𝑦 → (𝜓 → 𝜒)))
8	7	com12 33	. . . . 5 ⊢ (𝑥 = 𝑦 → (𝜑 → (𝜓 → 𝜒)))
9	8	a2d 30	. . . 4 ⊢ (𝑥 = 𝑦 → ((𝜑 → 𝜓) → (𝜑 → 𝜒)))
10	3, 6, 9	cbv3v 2369	. . 3 ⊢ (∀𝑥(𝜑 → 𝜓) → ∀𝑦(𝜑 → 𝜒))
11	4	19.21 2246	. . 3 ⊢ (∀𝑥(𝜑 → 𝜓) ↔ (𝜑 → ∀𝑥𝜓))
12	1	19.21 2246	. . 3 ⊢ (∀𝑦(𝜑 → 𝜒) ↔ (𝜑 → ∀𝑦𝜒))
13	10, 11, 12	3imtr3i 294	. 2 ⊢ ((𝜑 → ∀𝑥𝜓) → (𝜑 → ∀𝑦𝜒))
14	13	pm2.86i 111	1 ⊢ (𝜑 → (∀𝑥𝜓 → ∀𝑦𝜒))

This proof depends on syntax axioms:   → wi 4  ∀wal 1568  Ⅎwnf 1816

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-11 2195  ax-12 2216

This proof depends on definitions:  df-bi 210  df-or 862  df-ex 1813  df-nf 1817

This theorem is used by:  cbv2w  2371  cbvex1v  35531  dvelimalcased  35532  bj-cbv1hv  37492