Theorem ceqsex8v 3547

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

Hypotheses

Ref	Expression
ceqsex8v.1	⊢ 𝐴 ∈ V
ceqsex8v.2	⊢ 𝐵 ∈ V
ceqsex8v.3	⊢ 𝐶 ∈ V
ceqsex8v.4	⊢ 𝐷 ∈ V
ceqsex8v.5	⊢ 𝐸 ∈ V
ceqsex8v.6	⊢ 𝐹 ∈ V
ceqsex8v.7	⊢ 𝐺 ∈ V
ceqsex8v.8	⊢ 𝐻 ∈ V
ceqsex8v.9	⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜓))
ceqsex8v.10	⊢ (𝑦 = 𝐵 → (𝜓 ↔ 𝜒))
ceqsex8v.11	⊢ (𝑧 = 𝐶 → (𝜒 ↔ 𝜃))
ceqsex8v.12	⊢ (𝑤 = 𝐷 → (𝜃 ↔ 𝜏))
ceqsex8v.13	⊢ (𝑣 = 𝐸 → (𝜏 ↔ 𝜂))
ceqsex8v.14	⊢ (𝑢 = 𝐹 → (𝜂 ↔ 𝜁))
ceqsex8v.15	⊢ (𝑡 = 𝐺 → (𝜁 ↔ 𝜎))
ceqsex8v.16	⊢ (𝑠 = 𝐻 → (𝜎 ↔ 𝜌))

Assertion

Ref	Expression
ceqsex8v	⊢ (∃𝑥∃𝑦∃𝑧∃𝑤∃𝑣∃𝑢∃𝑡∃𝑠(((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻)) ∧ 𝜑) ↔ 𝜌)

Distinct variable groups:   𝑥,𝑦,𝑧,𝑤,𝑣,𝑢,𝑡,𝑠,𝐴   𝑥,𝐵,𝑦,𝑧,𝑤,𝑣,𝑢,𝑡,𝑠   𝑥,𝐶,𝑦,𝑧,𝑤,𝑣,𝑢,𝑡,𝑠   𝑥,𝐷,𝑦,𝑧,𝑤,𝑣,𝑢,𝑡,𝑠   𝑥,𝐸,𝑦,𝑧,𝑤,𝑣,𝑢,𝑡,𝑠   𝑥,𝐹,𝑦,𝑧,𝑤,𝑣,𝑢,𝑡,𝑠   𝑥,𝐺,𝑦,𝑧,𝑤,𝑣,𝑢,𝑡,𝑠   𝑥,𝐻,𝑦,𝑧,𝑤,𝑣,𝑢,𝑡,𝑠   𝜓,𝑥   𝜒,𝑦   𝜃,𝑧   𝜏,𝑤   𝜂,𝑣   𝜁,𝑢   𝜎,𝑡   𝜌,𝑠

Allowed substitution hints:   𝜑(𝑥,𝑦,𝑧,𝑤,𝑣,𝑢,𝑡,𝑠)   𝜓(𝑦,𝑧,𝑤,𝑣,𝑢,𝑡,𝑠)   𝜒(𝑥,𝑧,𝑤,𝑣,𝑢,𝑡,𝑠)   𝜃(𝑥,𝑦,𝑤,𝑣,𝑢,𝑡,𝑠)   𝜏(𝑥,𝑦,𝑧,𝑣,𝑢,𝑡,𝑠)   𝜂(𝑥,𝑦,𝑧,𝑤,𝑢,𝑡,𝑠)   𝜁(𝑥,𝑦,𝑧,𝑤,𝑣,𝑡,𝑠)   𝜎(𝑥,𝑦,𝑧,𝑤,𝑣,𝑢,𝑠)   𝜌(𝑥,𝑦,𝑧,𝑤,𝑣,𝑢,𝑡)

Proof of Theorem ceqsex8v

Step	Hyp	Ref	Expression
1		19.42vv 1952	. . . . . . 7 ⊢ (∃𝑡∃𝑠(((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)) ↔ (((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)))
2	1	2exbii 1843	. . . . . 6 ⊢ (∃𝑣∃𝑢∃𝑡∃𝑠(((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)) ↔ ∃𝑣∃𝑢(((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)))
3		19.42vv 1952	. . . . . 6 ⊢ (∃𝑣∃𝑢(((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)) ↔ (((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)))
4	2, 3	bitri 277	. . . . 5 ⊢ (∃𝑣∃𝑢∃𝑡∃𝑠(((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)) ↔ (((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)))
5		3anass 1090	. . . . . . . 8 ⊢ ((((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻)) ∧ 𝜑) ↔ (((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ (((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻)) ∧ 𝜑)))
6		df-3an 1084	. . . . . . . . 9 ⊢ (((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑) ↔ (((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻)) ∧ 𝜑))
7	6	anbi2i 624	. . . . . . . 8 ⊢ ((((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)) ↔ (((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ (((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻)) ∧ 𝜑)))
8	5, 7	bitr4i 280	. . . . . . 7 ⊢ ((((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻)) ∧ 𝜑) ↔ (((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)))
9	8	2exbii 1843	. . . . . 6 ⊢ (∃𝑡∃𝑠(((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻)) ∧ 𝜑) ↔ ∃𝑡∃𝑠(((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)))
10	9	2exbii 1843	. . . . 5 ⊢ (∃𝑣∃𝑢∃𝑡∃𝑠(((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻)) ∧ 𝜑) ↔ ∃𝑣∃𝑢∃𝑡∃𝑠(((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)))
11		df-3an 1084	. . . . 5 ⊢ (((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ ∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)) ↔ (((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)))
12	4, 10, 11	3bitr4i 305	. . . 4 ⊢ (∃𝑣∃𝑢∃𝑡∃𝑠(((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻)) ∧ 𝜑) ↔ ((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ ∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)))
13	12	2exbii 1843	. . 3 ⊢ (∃𝑧∃𝑤∃𝑣∃𝑢∃𝑡∃𝑠(((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻)) ∧ 𝜑) ↔ ∃𝑧∃𝑤((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ ∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)))
14	13	2exbii 1843	. 2 ⊢ (∃𝑥∃𝑦∃𝑧∃𝑤∃𝑣∃𝑢∃𝑡∃𝑠(((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻)) ∧ 𝜑) ↔ ∃𝑥∃𝑦∃𝑧∃𝑤((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ ∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)))
15		ceqsex8v.1	. . . 4 ⊢ 𝐴 ∈ V
16		ceqsex8v.2	. . . 4 ⊢ 𝐵 ∈ V
17		ceqsex8v.3	. . . 4 ⊢ 𝐶 ∈ V
18		ceqsex8v.4	. . . 4 ⊢ 𝐷 ∈ V
19		ceqsex8v.9	. . . . . 6 ⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜓))
20	19	3anbi3d 1436	. . . . 5 ⊢ (𝑥 = 𝐴 → (((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑) ↔ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜓)))
21	20	4exbidv 1921	. . . 4 ⊢ (𝑥 = 𝐴 → (∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑) ↔ ∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜓)))
22		ceqsex8v.10	. . . . . 6 ⊢ (𝑦 = 𝐵 → (𝜓 ↔ 𝜒))
23	22	3anbi3d 1436	. . . . 5 ⊢ (𝑦 = 𝐵 → (((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜓) ↔ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜒)))
24	23	4exbidv 1921	. . . 4 ⊢ (𝑦 = 𝐵 → (∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜓) ↔ ∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜒)))
25		ceqsex8v.11	. . . . . 6 ⊢ (𝑧 = 𝐶 → (𝜒 ↔ 𝜃))
26	25	3anbi3d 1436	. . . . 5 ⊢ (𝑧 = 𝐶 → (((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜒) ↔ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜃)))
27	26	4exbidv 1921	. . . 4 ⊢ (𝑧 = 𝐶 → (∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜒) ↔ ∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜃)))
28		ceqsex8v.12	. . . . . 6 ⊢ (𝑤 = 𝐷 → (𝜃 ↔ 𝜏))
29	28	3anbi3d 1436	. . . . 5 ⊢ (𝑤 = 𝐷 → (((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜃) ↔ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜏)))
30	29	4exbidv 1921	. . . 4 ⊢ (𝑤 = 𝐷 → (∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜃) ↔ ∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜏)))
31	15, 16, 17, 18, 21, 24, 27, 30	ceqsex4v 3545	. . 3 ⊢ (∃𝑥∃𝑦∃𝑧∃𝑤((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ ∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)) ↔ ∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜏))
32		ceqsex8v.5	. . . 4 ⊢ 𝐸 ∈ V
33		ceqsex8v.6	. . . 4 ⊢ 𝐹 ∈ V
34		ceqsex8v.7	. . . 4 ⊢ 𝐺 ∈ V
35		ceqsex8v.8	. . . 4 ⊢ 𝐻 ∈ V
36		ceqsex8v.13	. . . 4 ⊢ (𝑣 = 𝐸 → (𝜏 ↔ 𝜂))
37		ceqsex8v.14	. . . 4 ⊢ (𝑢 = 𝐹 → (𝜂 ↔ 𝜁))
38		ceqsex8v.15	. . . 4 ⊢ (𝑡 = 𝐺 → (𝜁 ↔ 𝜎))
39		ceqsex8v.16	. . . 4 ⊢ (𝑠 = 𝐻 → (𝜎 ↔ 𝜌))
40	32, 33, 34, 35, 36, 37, 38, 39	ceqsex4v 3545	. . 3 ⊢ (∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜏) ↔ 𝜌)
41	31, 40	bitri 277	. 2 ⊢ (∃𝑥∃𝑦∃𝑧∃𝑤((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷) ∧ ∃𝑣∃𝑢∃𝑡∃𝑠((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻) ∧ 𝜑)) ↔ 𝜌)
42	14, 41	bitri 277	1 ⊢ (∃𝑥∃𝑦∃𝑧∃𝑤∃𝑣∃𝑢∃𝑡∃𝑠(((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) ∧ (𝑧 = 𝐶 ∧ 𝑤 = 𝐷)) ∧ ((𝑣 = 𝐸 ∧ 𝑢 = 𝐹) ∧ (𝑡 = 𝐺 ∧ 𝑠 = 𝐻)) ∧ 𝜑) ↔ 𝜌)

Syntax hints:   → wi 4   ↔ wb 208   ∧ wa 398   ∧ w3a 1082   = wceq 1531  ∃wex 1774   ∈ wcel 2108  Vcvv 3493

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1790  ax-4 1804  ax-5 1905  ax-6 1964  ax-7 2009  ax-8 2110  ax-9 2118  ax-12 2170  ax-ext 2791

This theorem depends on definitions:  df-bi 209  df-an 399  df-3an 1084  df-ex 1775  df-nf 1779  df-cleq 2812  df-clel 2891

This theorem is referenced by: (None)