Theorem cbvmpo2 45551

Description: Rule to change the second bound variable in a maps-to function, using implicit substitution. (Contributed by Glauco Siliprandi, 26-Jun-2021.)

Hypotheses

Ref	Expression
cbvmpo2.1	⊢ Ⅎ𝑦𝐴
cbvmpo2.2	⊢ Ⅎ𝑤𝐴
cbvmpo2.3	⊢ Ⅎ𝑤𝐶
cbvmpo2.4	⊢ Ⅎ𝑦𝐸
cbvmpo2.5	⊢ (𝑦 = 𝑤 → 𝐶 = 𝐸)

Assertion

Ref	Expression
cbvmpo2	⊢ (𝑥 ∈ 𝐴, 𝑦 ∈ 𝐵 ↦ 𝐶) = (𝑥 ∈ 𝐴, 𝑤 ∈ 𝐵 ↦ 𝐸)

Distinct variable groups:   𝑤,𝐵,𝑦   𝑥,𝑤,𝑦

Allowed substitution hints:   𝐴(𝑥,𝑦,𝑤)   𝐵(𝑥)   𝐶(𝑥,𝑦,𝑤)   𝐸(𝑥,𝑦,𝑤)

Proof of Theorem cbvmpo2

Dummy variable 𝑢 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		cbvmpo2.2	. . . . . 6 ⊢ Ⅎ𝑤𝐴
2	1	nfcri 2894	. . . . 5 ⊢ Ⅎ𝑤 𝑥 ∈ 𝐴
3		nfcv 2902	. . . . . 6 ⊢ Ⅎ𝑤𝐵
4	3	nfcri 2894	. . . . 5 ⊢ Ⅎ𝑤 𝑦 ∈ 𝐵
5	2, 4	nfan 1906	. . . 4 ⊢ Ⅎ𝑤(𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵)
6		cbvmpo2.3	. . . . 5 ⊢ Ⅎ𝑤𝐶
7	6	nfeq2 2919	. . . 4 ⊢ Ⅎ𝑤 𝑢 = 𝐶
8	5, 7	nfan 1906	. . 3 ⊢ Ⅎ𝑤((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ∧ 𝑢 = 𝐶)
9		cbvmpo2.1	. . . . . 6 ⊢ Ⅎ𝑦𝐴
10	9	nfcri 2894	. . . . 5 ⊢ Ⅎ𝑦 𝑥 ∈ 𝐴
11		nfv 1921	. . . . 5 ⊢ Ⅎ𝑦 𝑤 ∈ 𝐵
12	10, 11	nfan 1906	. . . 4 ⊢ Ⅎ𝑦(𝑥 ∈ 𝐴 ∧ 𝑤 ∈ 𝐵)
13		cbvmpo2.4	. . . . 5 ⊢ Ⅎ𝑦𝐸
14	13	nfeq2 2919	. . . 4 ⊢ Ⅎ𝑦 𝑢 = 𝐸
15	12, 14	nfan 1906	. . 3 ⊢ Ⅎ𝑦((𝑥 ∈ 𝐴 ∧ 𝑤 ∈ 𝐵) ∧ 𝑢 = 𝐸)
16		eleq1w 2823	. . . . 5 ⊢ (𝑦 = 𝑤 → (𝑦 ∈ 𝐵 ↔ 𝑤 ∈ 𝐵))
17	16	anbi2d 636	. . . 4 ⊢ (𝑦 = 𝑤 → ((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ↔ (𝑥 ∈ 𝐴 ∧ 𝑤 ∈ 𝐵)))
18		cbvmpo2.5	. . . . 5 ⊢ (𝑦 = 𝑤 → 𝐶 = 𝐸)
19	18	eqeq2d 2751	. . . 4 ⊢ (𝑦 = 𝑤 → (𝑢 = 𝐶 ↔ 𝑢 = 𝐸))
20	17, 19	anbi12d 638	. . 3 ⊢ (𝑦 = 𝑤 → (((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ∧ 𝑢 = 𝐶) ↔ ((𝑥 ∈ 𝐴 ∧ 𝑤 ∈ 𝐵) ∧ 𝑢 = 𝐸)))
21	8, 15, 20	cbvoprab2 7451	. 2 ⊢ {⟨⟨𝑥, 𝑦⟩, 𝑢⟩ ∣ ((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ∧ 𝑢 = 𝐶)} = {⟨⟨𝑥, 𝑤⟩, 𝑢⟩ ∣ ((𝑥 ∈ 𝐴 ∧ 𝑤 ∈ 𝐵) ∧ 𝑢 = 𝐸)}
22		df-mpo 7368	. 2 ⊢ (𝑥 ∈ 𝐴, 𝑦 ∈ 𝐵 ↦ 𝐶) = {⟨⟨𝑥, 𝑦⟩, 𝑢⟩ ∣ ((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ∧ 𝑢 = 𝐶)}
23		df-mpo 7368	. 2 ⊢ (𝑥 ∈ 𝐴, 𝑤 ∈ 𝐵 ↦ 𝐸) = {⟨⟨𝑥, 𝑤⟩, 𝑢⟩ ∣ ((𝑥 ∈ 𝐴 ∧ 𝑤 ∈ 𝐵) ∧ 𝑢 = 𝐸)}
24	21, 22, 23	3eqtr4i 2773	1 ⊢ (𝑥 ∈ 𝐴, 𝑦 ∈ 𝐵 ↦ 𝐶) = (𝑥 ∈ 𝐴, 𝑤 ∈ 𝐵 ↦ 𝐸)

Syntax hints:   ∧ wa 396   = wceq 1547   ∈ wcel 2119  Ⅎwnfc 2887  {coprab 7364   ∈ cmpo 7365

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1802  ax-4 1816  ax-5 1917  ax-6 1974  ax-7 2015  ax-8 2121  ax-9 2129  ax-10 2152  ax-11 2168  ax-12 2189  ax-ext 2712

This theorem depends on definitions:  df-bi 208  df-an 397  df-or 854  df-3an 1094  df-tru 1550  df-fal 1560  df-ex 1787  df-nf 1791  df-sb 2074  df-clab 2719  df-cleq 2732  df-clel 2815  df-nfc 2889  df-rab 3393  df-v 3434  df-dif 3893  df-un 3895  df-ss 3907  df-nul 4269  df-if 4462  df-sn 4563  df-pr 4565  df-op 4569  df-oprab 7367  df-mpo 7368

This theorem is referenced by:  smflimlem4  47224