Theorem uniiunlem 3246

Description: A subset relationship useful for converting union to indexed union using dfiun2 or dfiun2g and intersection to indexed intersection using dfiin2 . (Contributed by NM, 5-Oct-2006.) (Proof shortened by Mario Carneiro, 26-Sep-2015.)

Assertion

Ref	Expression
uniiunlem	⊢ (∀𝑥 ∈ 𝐴 𝐵 ∈ 𝐷 → (∀𝑥 ∈ 𝐴 𝐵 ∈ 𝐶 ↔ {𝑦 ∣ ∃𝑥 ∈ 𝐴 𝑦 = 𝐵} ⊆ 𝐶))

Distinct variable groups:   𝑥,𝑦   𝑦,𝐴   𝑦,𝐵   𝑥,𝐶

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

Proof of Theorem uniiunlem

Dummy variable 𝑧 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		eqeq1 2184	. . . . . 6 ⊢ (𝑦 = 𝑧 → (𝑦 = 𝐵 ↔ 𝑧 = 𝐵))
2	1	rexbidv 2478	. . . . 5 ⊢ (𝑦 = 𝑧 → (∃𝑥 ∈ 𝐴 𝑦 = 𝐵 ↔ ∃𝑥 ∈ 𝐴 𝑧 = 𝐵))
3	2	cbvabv 2302	. . . 4 ⊢ {𝑦 ∣ ∃𝑥 ∈ 𝐴 𝑦 = 𝐵} = {𝑧 ∣ ∃𝑥 ∈ 𝐴 𝑧 = 𝐵}
4	3	sseq1i 3183	. . 3 ⊢ ({𝑦 ∣ ∃𝑥 ∈ 𝐴 𝑦 = 𝐵} ⊆ 𝐶 ↔ {𝑧 ∣ ∃𝑥 ∈ 𝐴 𝑧 = 𝐵} ⊆ 𝐶)
5		r19.23v 2586	. . . . 5 ⊢ (∀𝑥 ∈ 𝐴 (𝑧 = 𝐵 → 𝑧 ∈ 𝐶) ↔ (∃𝑥 ∈ 𝐴 𝑧 = 𝐵 → 𝑧 ∈ 𝐶))
6	5	albii 1470	. . . 4 ⊢ (∀𝑧∀𝑥 ∈ 𝐴 (𝑧 = 𝐵 → 𝑧 ∈ 𝐶) ↔ ∀𝑧(∃𝑥 ∈ 𝐴 𝑧 = 𝐵 → 𝑧 ∈ 𝐶))
7		ralcom4 2761	. . . 4 ⊢ (∀𝑥 ∈ 𝐴 ∀𝑧(𝑧 = 𝐵 → 𝑧 ∈ 𝐶) ↔ ∀𝑧∀𝑥 ∈ 𝐴 (𝑧 = 𝐵 → 𝑧 ∈ 𝐶))
8		abss 3226	. . . 4 ⊢ ({𝑧 ∣ ∃𝑥 ∈ 𝐴 𝑧 = 𝐵} ⊆ 𝐶 ↔ ∀𝑧(∃𝑥 ∈ 𝐴 𝑧 = 𝐵 → 𝑧 ∈ 𝐶))
9	6, 7, 8	3bitr4i 212	. . 3 ⊢ (∀𝑥 ∈ 𝐴 ∀𝑧(𝑧 = 𝐵 → 𝑧 ∈ 𝐶) ↔ {𝑧 ∣ ∃𝑥 ∈ 𝐴 𝑧 = 𝐵} ⊆ 𝐶)
10	4, 9	bitr4i 187	. 2 ⊢ ({𝑦 ∣ ∃𝑥 ∈ 𝐴 𝑦 = 𝐵} ⊆ 𝐶 ↔ ∀𝑥 ∈ 𝐴 ∀𝑧(𝑧 = 𝐵 → 𝑧 ∈ 𝐶))
11		nfv 1528	. . . . 5 ⊢ Ⅎ𝑧 𝐵 ∈ 𝐶
12		eleq1 2240	. . . . 5 ⊢ (𝑧 = 𝐵 → (𝑧 ∈ 𝐶 ↔ 𝐵 ∈ 𝐶))
13	11, 12	ceqsalg 2767	. . . 4 ⊢ (𝐵 ∈ 𝐷 → (∀𝑧(𝑧 = 𝐵 → 𝑧 ∈ 𝐶) ↔ 𝐵 ∈ 𝐶))
14	13	ralimi 2540	. . 3 ⊢ (∀𝑥 ∈ 𝐴 𝐵 ∈ 𝐷 → ∀𝑥 ∈ 𝐴 (∀𝑧(𝑧 = 𝐵 → 𝑧 ∈ 𝐶) ↔ 𝐵 ∈ 𝐶))
15		ralbi 2609	. . 3 ⊢ (∀𝑥 ∈ 𝐴 (∀𝑧(𝑧 = 𝐵 → 𝑧 ∈ 𝐶) ↔ 𝐵 ∈ 𝐶) → (∀𝑥 ∈ 𝐴 ∀𝑧(𝑧 = 𝐵 → 𝑧 ∈ 𝐶) ↔ ∀𝑥 ∈ 𝐴 𝐵 ∈ 𝐶))
16	14, 15	syl 14	. 2 ⊢ (∀𝑥 ∈ 𝐴 𝐵 ∈ 𝐷 → (∀𝑥 ∈ 𝐴 ∀𝑧(𝑧 = 𝐵 → 𝑧 ∈ 𝐶) ↔ ∀𝑥 ∈ 𝐴 𝐵 ∈ 𝐶))
17	10, 16	bitr2id 193	1 ⊢ (∀𝑥 ∈ 𝐴 𝐵 ∈ 𝐷 → (∀𝑥 ∈ 𝐴 𝐵 ∈ 𝐶 ↔ {𝑦 ∣ ∃𝑥 ∈ 𝐴 𝑦 = 𝐵} ⊆ 𝐶))

Syntax hints:   → wi 4   ↔ wb 105  ∀wal 1351   = wceq 1353   ∈ wcel 2148  {cab 2163  ∀wral 2455  ∃wrex 2456   ⊆ wss 3131

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 709  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-10 1505  ax-11 1506  ax-i12 1507  ax-bndl 1509  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-ext 2159

This theorem depends on definitions:  df-bi 117  df-tru 1356  df-nf 1461  df-sb 1763  df-clab 2164  df-cleq 2170  df-clel 2173  df-nfc 2308  df-ral 2460  df-rex 2461  df-v 2741  df-in 3137  df-ss 3144

This theorem is referenced by:  iunopn  13642