Theorem ceqsex4v 3503

Description: Elimination of four existential quantifiers, using implicit substitution. (Contributed by NM, 23-Sep-2011.)

Hypotheses

Ref	Expression
ceqsex4v.1	⊢ 𝐴 ∈ V
ceqsex4v.2	⊢ 𝐵 ∈ V
ceqsex4v.3	⊢ 𝐶 ∈ V
ceqsex4v.4	⊢ 𝐷 ∈ V
ceqsex4v.7	⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜓))
ceqsex4v.8	⊢ (𝑦 = 𝐵 → (𝜓 ↔ 𝜒))
ceqsex4v.9	⊢ (𝑧 = 𝐶 → (𝜒 ↔ 𝜃))
ceqsex4v.10	⊢ (𝑤 = 𝐷 → (𝜃 ↔ 𝜏))

Assertion

Ref	Expression
ceqsex4v	⊢ (∃𝑥∃𝑦∃𝑧∃𝑤((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ 𝜑) ↔ 𝜏)

Distinct variable groups:   𝑥,𝑦,𝑧,𝑤,𝐴   𝑥,𝐵,𝑦,𝑧,𝑤   𝑥,𝐶,𝑦,𝑧,𝑤   𝑥,𝐷,𝑦,𝑧,𝑤   𝜓,𝑥   𝜒,𝑦   𝜃,𝑧   𝜏,𝑤

Allowed substitution hints:   𝜑(𝑥, 𝑦, 𝑧, 𝑤)   𝜓(𝑦, 𝑧, 𝑤)   𝜒(𝑥, 𝑧, 𝑤)   𝜃(𝑥, 𝑦, 𝑤)   𝜏(𝑥, 𝑦, 𝑧)

Proof of Theorem ceqsex4v

Step	Hyp	Ref	Expression
1		19.42vv 1990	. . . 4 ⊢ (∃𝑧∃𝑤((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜑)) ↔ ((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ ∃𝑧∃𝑤(𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜑)))
2		3anass 1111	. . . . . 6 ⊢ (((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ 𝜑) ↔ ((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ ((𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ 𝜑)))
3		df-3an 1105	. . . . . . 7 ⊢ ((𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜑) ↔ ((𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ 𝜑))
4	3	anbi2i 635	. . . . . 6 ⊢ (((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜑)) ↔ ((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ ((𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ 𝜑)))
5	2, 4	bitr4i 281	. . . . 5 ⊢ (((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ 𝜑) ↔ ((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜑)))
6	5	2exbii 1882	. . . 4 ⊢ (∃𝑧∃𝑤((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ 𝜑) ↔ ∃𝑧∃𝑤((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜑)))
7		df-3an 1105	. . . 4 ⊢ ((𝑥 = 𝐴 ∧ 𝑦 = 𝐵 ∧ ∃𝑧∃𝑤(𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜑)) ↔ ((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ ∃𝑧∃𝑤(𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜑)))
8	1, 6, 7	3bitr4i 306	. . 3 ⊢ (∃𝑧∃𝑤((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ 𝜑) ↔ (𝑥 = 𝐴 ∧ 𝑦 = 𝐵 ∧ ∃𝑧∃𝑤(𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜑)))
9	8	2exbii 1882	. 2 ⊢ (∃𝑥∃𝑦∃𝑧∃𝑤((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ 𝜑) ↔ ∃𝑥∃𝑦(𝑥 = 𝐴 ∧ 𝑦 = 𝐵 ∧ ∃𝑧∃𝑤(𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜑)))
10		ceqsex4v.1	. . 3 ⊢ 𝐴 ∈ V
11		ceqsex4v.2	. . 3 ⊢ 𝐵 ∈ V
12		ceqsex4v.7	. . . . 5 ⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜓))
13	12	3anbi3d 1470	. . . 4 ⊢ (𝑥 = 𝐴 → ((𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜑) ↔ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜓)))
14	13	2exbidv 1957	. . 3 ⊢ (𝑥 = 𝐴 → (∃𝑧∃𝑤(𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜑) ↔ ∃𝑧∃𝑤(𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜓)))
15		ceqsex4v.8	. . . . 5 ⊢ (𝑦 = 𝐵 → (𝜓 ↔ 𝜒))
16	15	3anbi3d 1470	. . . 4 ⊢ (𝑦 = 𝐵 → ((𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜓) ↔ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜒)))
17	16	2exbidv 1957	. . 3 ⊢ (𝑦 = 𝐵 → (∃𝑧∃𝑤(𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜓) ↔ ∃𝑧∃𝑤(𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜒)))
18	10, 11, 14, 17	ceqsex2v 3501	. 2 ⊢ (∃𝑥∃𝑦(𝑥 = 𝐴 ∧ 𝑦 = 𝐵 ∧ ∃𝑧∃𝑤(𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜑)) ↔ ∃𝑧∃𝑤(𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜒))
19		ceqsex4v.3	. . 3 ⊢ 𝐶 ∈ V
20		ceqsex4v.4	. . 3 ⊢ 𝐷 ∈ V
21		ceqsex4v.9	. . 3 ⊢ (𝑧 = 𝐶 → (𝜒 ↔ 𝜃))
22		ceqsex4v.10	. . 3 ⊢ (𝑤 = 𝐷 → (𝜃 ↔ 𝜏))
23	19, 20, 21, 22	ceqsex2v 3501	. 2 ⊢ (∃𝑧∃𝑤(𝑧 = 𝐶 ∧ 𝑤 = 𝐷 ∧ 𝜒) ↔ 𝜏)
24	9, 18, 23	3bitri 300	1 ⊢ (∃𝑥∃𝑦∃𝑧∃𝑤((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ 𝜑) ↔ 𝜏)

This proof depends on syntax axioms:   → wi 4   ↔ wb 209   ∧ wa 401   ∧ w3a 1103   = wceq 1570  ∃wex 1812   ∈ wcel 2145  Vcvv 3450

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2147

This proof depends on definitions:  df-bi 210  df-an 402  df-3an 1105  df-ex 1813  df-clel 2835

This theorem is used by:  ceqsex8v  3505  dihopelvalcpre  42225