Theorem nfimd 1897

Description: If in a context 𝑥 is not free in 𝜓 and 𝜒, then it is not free in (𝜓 → 𝜒). Deduction form of nfim 1899. (Contributed by Mario Carneiro, 24-Sep-2016.) (Proof shortened by Wolf Lammen, 30-Dec-2017.) df-nf 1786 changed. (Revised by Wolf Lammen, 18-Sep-2021.) Eliminate curried form of nfimt 1898. (Revised by Wolf Lammen, 10-Jul-2022.)

Hypotheses

Ref	Expression
nfimd.1	⊢ (𝜑 → Ⅎ𝑥𝜓)
nfimd.2	⊢ (𝜑 → Ⅎ𝑥𝜒)

Assertion

Ref	Expression
nfimd	⊢ (𝜑 → Ⅎ𝑥(𝜓 → 𝜒))

Proof of Theorem nfimd

Step	Hyp	Ref	Expression
1		19.35 1880	. . . 4 ⊢ (∃𝑥(𝜓 → 𝜒) ↔ (∀𝑥𝜓 → ∃𝑥𝜒))
2	1	biimpi 215	. . 3 ⊢ (∃𝑥(𝜓 → 𝜒) → (∀𝑥𝜓 → ∃𝑥𝜒))
3		nfimd.1	. . . . 5 ⊢ (𝜑 → Ⅎ𝑥𝜓)
4	3	nfrd 1793	. . . 4 ⊢ (𝜑 → (∃𝑥𝜓 → ∀𝑥𝜓))
5		nfimd.2	. . . . 5 ⊢ (𝜑 → Ⅎ𝑥𝜒)
6	5	nfrd 1793	. . . 4 ⊢ (𝜑 → (∃𝑥𝜒 → ∀𝑥𝜒))
7	4, 6	imim12d 81	. . 3 ⊢ (𝜑 → ((∀𝑥𝜓 → ∃𝑥𝜒) → (∃𝑥𝜓 → ∀𝑥𝜒)))
8		19.38 1841	. . 3 ⊢ ((∃𝑥𝜓 → ∀𝑥𝜒) → ∀𝑥(𝜓 → 𝜒))
9	2, 7, 8	syl56 36	. 2 ⊢ (𝜑 → (∃𝑥(𝜓 → 𝜒) → ∀𝑥(𝜓 → 𝜒)))
10	9	nfd 1792	1 ⊢ (𝜑 → Ⅎ𝑥(𝜓 → 𝜒))

Syntax hints:   → wi 4  ∀wal 1539  ∃wex 1781  Ⅎwnf 1785

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811

This theorem depends on definitions:  df-bi 206  df-ex 1782  df-nf 1786

This theorem is referenced by:  nfimt  1898  nfand  1900  nfbid  1905  nfim1  2192  hbimd  2294  dvelimhw  2341  dvelimf  2446  nfmod2  2551  nfmodv  2552  nfabdw  2925  nfraldw  3290  nfraldwOLD  3300  nfrald  3343  nfifd  4520  nfixpw  8861  nfixp  8862  axrepndlem1  10537  axrepndlem2  10538  axunndlem1  10540  axunnd  10541  axpowndlem2  10543  axpowndlem3  10544  axpowndlem4  10545  axregndlem2  10548  axregnd  10549  axinfndlem1  10550  axinfnd  10551  axacndlem4  10555  axacndlem5  10556  axacnd  10557  bj-dvelimdv  35393  wl-mo2df  36098  wl-mo2t  36103  riotasv2d  37492  nfintd  47238