Theorem rexiunxp 4872

Description: Write a double restricted quantification as one universal quantifier. In this version of rexxp 4874, 𝐵(𝑦) is not assumed to be constant. (Contributed by Mario Carneiro, 14-Feb-2015.)

Hypothesis

Ref	Expression
ralxp.1	⊢ (𝑥 = ⟨𝑦, 𝑧⟩ → (𝜑 ↔ 𝜓))

Assertion

Ref	Expression
rexiunxp	⊢ (∃𝑥 ∈ ∪ 𝑦 ∈ 𝐴 ({𝑦} × 𝐵)𝜑 ↔ ∃𝑦 ∈ 𝐴 ∃𝑧 ∈ 𝐵 𝜓)

Distinct variable groups:   𝑥,𝑦,𝑧,𝐴   𝑥,𝐵,𝑧   𝜑,𝑦,𝑧   𝜓,𝑥

Allowed substitution hints:   𝜑(𝑥)   𝜓(𝑦,𝑧)   𝐵(𝑦)

Proof of Theorem rexiunxp

Step	Hyp	Ref	Expression
1		eliunxp 4869	. . . . . 6 ⊢ (𝑥 ∈ ∪ 𝑦 ∈ 𝐴 ({𝑦} × 𝐵) ↔ ∃𝑦∃𝑧(𝑥 = ⟨𝑦, 𝑧⟩ ∧ (𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵)))
2	1	anbi1i 458	. . . . 5 ⊢ ((𝑥 ∈ ∪ 𝑦 ∈ 𝐴 ({𝑦} × 𝐵) ∧ 𝜑) ↔ (∃𝑦∃𝑧(𝑥 = ⟨𝑦, 𝑧⟩ ∧ (𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵)) ∧ 𝜑))
3		19.41vv 1952	. . . . 5 ⊢ (∃𝑦∃𝑧((𝑥 = ⟨𝑦, 𝑧⟩ ∧ (𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵)) ∧ 𝜑) ↔ (∃𝑦∃𝑧(𝑥 = ⟨𝑦, 𝑧⟩ ∧ (𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵)) ∧ 𝜑))
4	2, 3	bitr4i 187	. . . 4 ⊢ ((𝑥 ∈ ∪ 𝑦 ∈ 𝐴 ({𝑦} × 𝐵) ∧ 𝜑) ↔ ∃𝑦∃𝑧((𝑥 = ⟨𝑦, 𝑧⟩ ∧ (𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵)) ∧ 𝜑))
5	4	exbii 1653	. . 3 ⊢ (∃𝑥(𝑥 ∈ ∪ 𝑦 ∈ 𝐴 ({𝑦} × 𝐵) ∧ 𝜑) ↔ ∃𝑥∃𝑦∃𝑧((𝑥 = ⟨𝑦, 𝑧⟩ ∧ (𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵)) ∧ 𝜑))
6		exrot3 1738	. . . 4 ⊢ (∃𝑥∃𝑦∃𝑧((𝑥 = ⟨𝑦, 𝑧⟩ ∧ (𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵)) ∧ 𝜑) ↔ ∃𝑦∃𝑧∃𝑥((𝑥 = ⟨𝑦, 𝑧⟩ ∧ (𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵)) ∧ 𝜑))
7		anass 401	. . . . . . 7 ⊢ (((𝑥 = ⟨𝑦, 𝑧⟩ ∧ (𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵)) ∧ 𝜑) ↔ (𝑥 = ⟨𝑦, 𝑧⟩ ∧ ((𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵) ∧ 𝜑)))
8	7	exbii 1653	. . . . . 6 ⊢ (∃𝑥((𝑥 = ⟨𝑦, 𝑧⟩ ∧ (𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵)) ∧ 𝜑) ↔ ∃𝑥(𝑥 = ⟨𝑦, 𝑧⟩ ∧ ((𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵) ∧ 𝜑)))
9		vex 2805	. . . . . . . 8 ⊢ 𝑦 ∈ V
10		vex 2805	. . . . . . . 8 ⊢ 𝑧 ∈ V
11	9, 10	opex 4321	. . . . . . 7 ⊢ ⟨𝑦, 𝑧⟩ ∈ V
12		ralxp.1	. . . . . . . 8 ⊢ (𝑥 = ⟨𝑦, 𝑧⟩ → (𝜑 ↔ 𝜓))
13	12	anbi2d 464	. . . . . . 7 ⊢ (𝑥 = ⟨𝑦, 𝑧⟩ → (((𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵) ∧ 𝜑) ↔ ((𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵) ∧ 𝜓)))
14	11, 13	ceqsexv 2842	. . . . . 6 ⊢ (∃𝑥(𝑥 = ⟨𝑦, 𝑧⟩ ∧ ((𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵) ∧ 𝜑)) ↔ ((𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵) ∧ 𝜓))
15	8, 14	bitri 184	. . . . 5 ⊢ (∃𝑥((𝑥 = ⟨𝑦, 𝑧⟩ ∧ (𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵)) ∧ 𝜑) ↔ ((𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵) ∧ 𝜓))
16	15	2exbii 1654	. . . 4 ⊢ (∃𝑦∃𝑧∃𝑥((𝑥 = ⟨𝑦, 𝑧⟩ ∧ (𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵)) ∧ 𝜑) ↔ ∃𝑦∃𝑧((𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵) ∧ 𝜓))
17	6, 16	bitri 184	. . 3 ⊢ (∃𝑥∃𝑦∃𝑧((𝑥 = ⟨𝑦, 𝑧⟩ ∧ (𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵)) ∧ 𝜑) ↔ ∃𝑦∃𝑧((𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵) ∧ 𝜓))
18	5, 17	bitri 184	. 2 ⊢ (∃𝑥(𝑥 ∈ ∪ 𝑦 ∈ 𝐴 ({𝑦} × 𝐵) ∧ 𝜑) ↔ ∃𝑦∃𝑧((𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵) ∧ 𝜓))
19		df-rex 2516	. 2 ⊢ (∃𝑥 ∈ ∪ 𝑦 ∈ 𝐴 ({𝑦} × 𝐵)𝜑 ↔ ∃𝑥(𝑥 ∈ ∪ 𝑦 ∈ 𝐴 ({𝑦} × 𝐵) ∧ 𝜑))
20		r2ex 2552	. 2 ⊢ (∃𝑦 ∈ 𝐴 ∃𝑧 ∈ 𝐵 𝜓 ↔ ∃𝑦∃𝑧((𝑦 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵) ∧ 𝜓))
21	18, 19, 20	3bitr4i 212	1 ⊢ (∃𝑥 ∈ ∪ 𝑦 ∈ 𝐴 ({𝑦} × 𝐵)𝜑 ↔ ∃𝑦 ∈ 𝐴 ∃𝑧 ∈ 𝐵 𝜓)

Syntax hints:   → wi 4   ∧ wa 104   ↔ wb 105   = wceq 1397  ∃wex 1540   ∈ wcel 2202  ∃wrex 2511  {csn 3669  ⟨cop 3672  ∪ ciun 3970   × cxp 4723

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 716  ax-5 1495  ax-7 1496  ax-gen 1497  ax-ie1 1541  ax-ie2 1542  ax-8 1552  ax-10 1553  ax-11 1554  ax-i12 1555  ax-bndl 1557  ax-4 1558  ax-17 1574  ax-i9 1578  ax-ial 1582  ax-i5r 1583  ax-14 2205  ax-ext 2213  ax-sep 4207  ax-pow 4264  ax-pr 4299

This theorem depends on definitions:  df-bi 117  df-3an 1006  df-tru 1400  df-nf 1509  df-sb 1811  df-clab 2218  df-cleq 2224  df-clel 2227  df-nfc 2363  df-ral 2515  df-rex 2516  df-v 2804  df-sbc 3032  df-csb 3128  df-un 3204  df-in 3206  df-ss 3213  df-pw 3654  df-sn 3675  df-pr 3676  df-op 3678  df-iun 3972  df-opab 4151  df-xp 4731  df-rel 4732

This theorem is referenced by:  rexxp  4874