Theorem cbvrexcsf 3201

Description: A more general version of cbvrexf 2769 that has no distinct variable restrictions. Changes bound variables using implicit substitution. (Contributed by Andrew Salmon, 13-Jul-2011.) (Proof shortened by Mario Carneiro, 7-Dec-2014.)

Hypotheses

Ref	Expression
cbvralcsf.1	⊢ Ⅎ𝑦𝐴
cbvralcsf.2	⊢ Ⅎ𝑥𝐵
cbvralcsf.3	⊢ Ⅎ𝑦𝜑
cbvralcsf.4	⊢ Ⅎ𝑥𝜓
cbvralcsf.5	⊢ (𝑥 = 𝑦 → 𝐴 = 𝐵)
cbvralcsf.6	⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))

Assertion

Ref	Expression
cbvrexcsf	⊢ (∃𝑥 ∈ 𝐴 𝜑 ↔ ∃𝑦 ∈ 𝐵 𝜓)

Proof of Theorem cbvrexcsf

Dummy variables 𝑣 𝑧 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		nfv 1577	. . . 4 ⊢ Ⅎ𝑧(𝑥 ∈ 𝐴 ∧ 𝜑)
2		nfcsb1v 3170	. . . . . 6 ⊢ Ⅎ𝑥⦋𝑧 / 𝑥⦌𝐴
3	2	nfcri 2378	. . . . 5 ⊢ Ⅎ𝑥 𝑧 ∈ ⦋𝑧 / 𝑥⦌𝐴
4		nfsbc1v 3060	. . . . 5 ⊢ Ⅎ𝑥[𝑧 / 𝑥]𝜑
5	3, 4	nfan 1614	. . . 4 ⊢ Ⅎ𝑥(𝑧 ∈ ⦋𝑧 / 𝑥⦌𝐴 ∧ [𝑧 / 𝑥]𝜑)
6		id 19	. . . . . 6 ⊢ (𝑥 = 𝑧 → 𝑥 = 𝑧)
7		csbeq1a 3146	. . . . . 6 ⊢ (𝑥 = 𝑧 → 𝐴 = ⦋𝑧 / 𝑥⦌𝐴)
8	6, 7	eleq12d 2303	. . . . 5 ⊢ (𝑥 = 𝑧 → (𝑥 ∈ 𝐴 ↔ 𝑧 ∈ ⦋𝑧 / 𝑥⦌𝐴))
9		sbceq1a 3051	. . . . 5 ⊢ (𝑥 = 𝑧 → (𝜑 ↔ [𝑧 / 𝑥]𝜑))
10	8, 9	anbi12d 473	. . . 4 ⊢ (𝑥 = 𝑧 → ((𝑥 ∈ 𝐴 ∧ 𝜑) ↔ (𝑧 ∈ ⦋𝑧 / 𝑥⦌𝐴 ∧ [𝑧 / 𝑥]𝜑)))
11	1, 5, 10	cbvex 1805	. . 3 ⊢ (∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ∃𝑧(𝑧 ∈ ⦋𝑧 / 𝑥⦌𝐴 ∧ [𝑧 / 𝑥]𝜑))
12		nfcv 2384	. . . . . . 7 ⊢ Ⅎ𝑦𝑧
13		cbvralcsf.1	. . . . . . 7 ⊢ Ⅎ𝑦𝐴
14	12, 13	nfcsb 3175	. . . . . 6 ⊢ Ⅎ𝑦⦋𝑧 / 𝑥⦌𝐴
15	14	nfcri 2378	. . . . 5 ⊢ Ⅎ𝑦 𝑧 ∈ ⦋𝑧 / 𝑥⦌𝐴
16		cbvralcsf.3	. . . . . 6 ⊢ Ⅎ𝑦𝜑
17	12, 16	nfsbc 3062	. . . . 5 ⊢ Ⅎ𝑦[𝑧 / 𝑥]𝜑
18	15, 17	nfan 1614	. . . 4 ⊢ Ⅎ𝑦(𝑧 ∈ ⦋𝑧 / 𝑥⦌𝐴 ∧ [𝑧 / 𝑥]𝜑)
19		nfv 1577	. . . 4 ⊢ Ⅎ𝑧(𝑦 ∈ 𝐵 ∧ 𝜓)
20		id 19	. . . . . 6 ⊢ (𝑧 = 𝑦 → 𝑧 = 𝑦)
21		csbeq1 3140	. . . . . . 7 ⊢ (𝑧 = 𝑦 → ⦋𝑧 / 𝑥⦌𝐴 = ⦋𝑦 / 𝑥⦌𝐴)
22		df-csb 3138	. . . . . . . 8 ⊢ ⦋𝑦 / 𝑥⦌𝐴 = {𝑣 ∣ [𝑦 / 𝑥]𝑣 ∈ 𝐴}
23		cbvralcsf.2	. . . . . . . . . . . 12 ⊢ Ⅎ𝑥𝐵
24	23	nfcri 2378	. . . . . . . . . . 11 ⊢ Ⅎ𝑥 𝑣 ∈ 𝐵
25		cbvralcsf.5	. . . . . . . . . . . 12 ⊢ (𝑥 = 𝑦 → 𝐴 = 𝐵)
26	25	eleq2d 2302	. . . . . . . . . . 11 ⊢ (𝑥 = 𝑦 → (𝑣 ∈ 𝐴 ↔ 𝑣 ∈ 𝐵))
27	24, 26	sbie 1840	. . . . . . . . . 10 ⊢ ([𝑦 / 𝑥]𝑣 ∈ 𝐴 ↔ 𝑣 ∈ 𝐵)
28		sbsbc 3045	. . . . . . . . . 10 ⊢ ([𝑦 / 𝑥]𝑣 ∈ 𝐴 ↔ [𝑦 / 𝑥]𝑣 ∈ 𝐴)
29	27, 28	bitr3i 186	. . . . . . . . 9 ⊢ (𝑣 ∈ 𝐵 ↔ [𝑦 / 𝑥]𝑣 ∈ 𝐴)
30	29	abbi2i 2347	. . . . . . . 8 ⊢ 𝐵 = {𝑣 ∣ [𝑦 / 𝑥]𝑣 ∈ 𝐴}
31	22, 30	eqtr4i 2256	. . . . . . 7 ⊢ ⦋𝑦 / 𝑥⦌𝐴 = 𝐵
32	21, 31	eqtrdi 2281	. . . . . 6 ⊢ (𝑧 = 𝑦 → ⦋𝑧 / 𝑥⦌𝐴 = 𝐵)
33	20, 32	eleq12d 2303	. . . . 5 ⊢ (𝑧 = 𝑦 → (𝑧 ∈ ⦋𝑧 / 𝑥⦌𝐴 ↔ 𝑦 ∈ 𝐵))
34		dfsbcq 3043	. . . . . 6 ⊢ (𝑧 = 𝑦 → ([𝑧 / 𝑥]𝜑 ↔ [𝑦 / 𝑥]𝜑))
35		sbsbc 3045	. . . . . . 7 ⊢ ([𝑦 / 𝑥]𝜑 ↔ [𝑦 / 𝑥]𝜑)
36		cbvralcsf.4	. . . . . . . 8 ⊢ Ⅎ𝑥𝜓
37		cbvralcsf.6	. . . . . . . 8 ⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))
38	36, 37	sbie 1840	. . . . . . 7 ⊢ ([𝑦 / 𝑥]𝜑 ↔ 𝜓)
39	35, 38	bitr3i 186	. . . . . 6 ⊢ ([𝑦 / 𝑥]𝜑 ↔ 𝜓)
40	34, 39	bitrdi 196	. . . . 5 ⊢ (𝑧 = 𝑦 → ([𝑧 / 𝑥]𝜑 ↔ 𝜓))
41	33, 40	anbi12d 473	. . . 4 ⊢ (𝑧 = 𝑦 → ((𝑧 ∈ ⦋𝑧 / 𝑥⦌𝐴 ∧ [𝑧 / 𝑥]𝜑) ↔ (𝑦 ∈ 𝐵 ∧ 𝜓)))
42	18, 19, 41	cbvex 1805	. . 3 ⊢ (∃𝑧(𝑧 ∈ ⦋𝑧 / 𝑥⦌𝐴 ∧ [𝑧 / 𝑥]𝜑) ↔ ∃𝑦(𝑦 ∈ 𝐵 ∧ 𝜓))
43	11, 42	bitri 184	. 2 ⊢ (∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ∃𝑦(𝑦 ∈ 𝐵 ∧ 𝜓))
44		df-rex 2526	. 2 ⊢ (∃𝑥 ∈ 𝐴 𝜑 ↔ ∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑))
45		df-rex 2526	. 2 ⊢ (∃𝑦 ∈ 𝐵 𝜓 ↔ ∃𝑦(𝑦 ∈ 𝐵 ∧ 𝜓))
46	43, 44, 45	3bitr4i 212	1 ⊢ (∃𝑥 ∈ 𝐴 𝜑 ↔ ∃𝑦 ∈ 𝐵 𝜓)

Syntax hints:   → wi 4   ∧ wa 104   ↔ wb 105   = wceq 1398  Ⅎwnf 1509  ∃wex 1541  [wsb 1811   ∈ wcel 2203  {cab 2218  Ⅎwnfc 2371  ∃wrex 2521  [wsbc 3041  ⦋csb 3137

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 717  ax-5 1496  ax-7 1497  ax-gen 1498  ax-ie1 1542  ax-ie2 1543  ax-8 1553  ax-10 1554  ax-11 1555  ax-i12 1556  ax-bndl 1558  ax-4 1559  ax-17 1575  ax-i9 1579  ax-ial 1583  ax-i5r 1584  ax-ext 2214

This theorem depends on definitions:  df-bi 117  df-tru 1401  df-nf 1510  df-sb 1812  df-clab 2219  df-cleq 2225  df-clel 2228  df-nfc 2373  df-rex 2526  df-sbc 3042  df-csb 3138

This theorem is referenced by:  cbvrexv2  3205