3cyclfrgrrn1 - Metamath Proof Explorer

	Metamath Proof Explorer		< Previous Next > Nearby theorems
Mirrors > Home > MPE Home > Th. List > 3cyclfrgrrn1		Structured version Visualization version GIF version

Theorem 3cyclfrgrrn1 30577

Description: Every vertex in a friendship graph (with more than 1 vertex) is part of a 3-cycle. (Contributed by Alexander van der Vekens, 16-Nov-2017.) (Revised by AV, 2-Apr-2021.)

**Hypotheses**
Ref	Expression
3cyclfrgrrn1.v	⊢ 𝑉 = (Vtx‘𝐺)
3cyclfrgrrn1.e	⊢ 𝐸 = (Edg‘𝐺)

**Assertion**
Ref	Expression
3cyclfrgrrn1	⊢ ((𝐺 ∈ FriendGraph ∧ (𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) ∧ 𝐴 ≠ 𝐶) → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))

Distinct variable groups: 𝐴,𝑏,𝑐 𝐸,𝑏,𝑐 𝑉,𝑏,𝑐 Allowed substitution hints: 𝐶(𝑏,𝑐) 𝐺(𝑏,𝑐)

Proof of Theorem 3cyclfrgrrn1 Dummy variables 𝑎 𝑥 𝑧 𝑦 𝑢 𝑣 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		3cyclfrgrrn1.v	. . . 4 ⊢ 𝑉 = (Vtx‘𝐺)
2		3cyclfrgrrn1.e	. . . 4 ⊢ 𝐸 = (Edg‘𝐺)
3	1, 2	2pthfrgrrn2 30575	. . 3 ⊢ (𝐺 ∈ FriendGraph → ∀𝑎 ∈ 𝑉 ∀𝑧 ∈ (𝑉 ∖ {𝑎})∃𝑥 ∈ 𝑉 (({𝑎, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝑎 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)))
4		necom 3017	. . . . . . . . . . . 12 ⊢ (𝐴 ≠ 𝐶 ↔ 𝐶 ≠ 𝐴)
5		eldifsn 4758	. . . . . . . . . . . . 13 ⊢ (𝐶 ∈ (𝑉 ∖ {𝐴}) ↔ (𝐶 ∈ 𝑉 ∧ 𝐶 ≠ 𝐴))
6	5	simplbi2com 507	. . . . . . . . . . . 12 ⊢ (𝐶 ≠ 𝐴 → (𝐶 ∈ 𝑉 → 𝐶 ∈ (𝑉 ∖ {𝐴})))
7	4, 6	sylbi 220	. . . . . . . . . . 11 ⊢ (𝐴 ≠ 𝐶 → (𝐶 ∈ 𝑉 → 𝐶 ∈ (𝑉 ∖ {𝐴})))
8	7	com12 33	. . . . . . . . . 10 ⊢ (𝐶 ∈ 𝑉 → (𝐴 ≠ 𝐶 → 𝐶 ∈ (𝑉 ∖ {𝐴})))
9	8	adantl 486	. . . . . . . . 9 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) → (𝐴 ≠ 𝐶 → 𝐶 ∈ (𝑉 ∖ {𝐴})))
10	9	imp 411	. . . . . . . 8 ⊢ (((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) ∧ 𝐴 ≠ 𝐶) → 𝐶 ∈ (𝑉 ∖ {𝐴}))
11		sneq 4604	. . . . . . . . . . . 12 ⊢ (𝑎 = 𝐴 → {𝑎} = {𝐴})
12	11	difeq2d 4089	. . . . . . . . . . 11 ⊢ (𝑎 = 𝐴 → (𝑉 ∖ {𝑎}) = (𝑉 ∖ {𝐴}))
13		preq1 4704	. . . . . . . . . . . . . . 15 ⊢ (𝑎 = 𝐴 → {𝑎, 𝑥} = {𝐴, 𝑥})
14	13	eleq1d 2854	. . . . . . . . . . . . . 14 ⊢ (𝑎 = 𝐴 → ({𝑎, 𝑥} ∈ 𝐸 ↔ {𝐴, 𝑥} ∈ 𝐸))
15	14	anbi1d 642	. . . . . . . . . . . . 13 ⊢ (𝑎 = 𝐴 → (({𝑎, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ↔ ({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸)))
16		neeq1 3026	. . . . . . . . . . . . . 14 ⊢ (𝑎 = 𝐴 → (𝑎 ≠ 𝑥 ↔ 𝐴 ≠ 𝑥))
17	16	anbi1d 642	. . . . . . . . . . . . 13 ⊢ (𝑎 = 𝐴 → ((𝑎 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧) ↔ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)))
18	15, 17	anbi12d 643	. . . . . . . . . . . 12 ⊢ (𝑎 = 𝐴 → ((({𝑎, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝑎 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)) ↔ (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧))))
19	18	rexbidv 3195	. . . . . . . . . . 11 ⊢ (𝑎 = 𝐴 → (∃𝑥 ∈ 𝑉 (({𝑎, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝑎 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)) ↔ ∃𝑥 ∈ 𝑉 (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧))))
20	12, 19	raleqbidv 3345	. . . . . . . . . 10 ⊢ (𝑎 = 𝐴 → (∀𝑧 ∈ (𝑉 ∖ {𝑎})∃𝑥 ∈ 𝑉 (({𝑎, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝑎 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)) ↔ ∀𝑧 ∈ (𝑉 ∖ {𝐴})∃𝑥 ∈ 𝑉 (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧))))
21	20	rspcv 3586	. . . . . . . . 9 ⊢ (𝐴 ∈ 𝑉 → (∀𝑎 ∈ 𝑉 ∀𝑧 ∈ (𝑉 ∖ {𝑎})∃𝑥 ∈ 𝑉 (({𝑎, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝑎 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)) → ∀𝑧 ∈ (𝑉 ∖ {𝐴})∃𝑥 ∈ 𝑉 (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧))))
22	21	ad2antrr 738	. . . . . . . 8 ⊢ (((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) ∧ 𝐴 ≠ 𝐶) → (∀𝑎 ∈ 𝑉 ∀𝑧 ∈ (𝑉 ∖ {𝑎})∃𝑥 ∈ 𝑉 (({𝑎, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝑎 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)) → ∀𝑧 ∈ (𝑉 ∖ {𝐴})∃𝑥 ∈ 𝑉 (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧))))
23		preq2 4705	. . . . . . . . . . . . 13 ⊢ (𝑧 = 𝐶 → {𝑥, 𝑧} = {𝑥, 𝐶})
24	23	eleq1d 2854	. . . . . . . . . . . 12 ⊢ (𝑧 = 𝐶 → ({𝑥, 𝑧} ∈ 𝐸 ↔ {𝑥, 𝐶} ∈ 𝐸))
25	24	anbi2d 641	. . . . . . . . . . 11 ⊢ (𝑧 = 𝐶 → (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ↔ ({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸)))
26		neeq2 3027	. . . . . . . . . . . 12 ⊢ (𝑧 = 𝐶 → (𝑥 ≠ 𝑧 ↔ 𝑥 ≠ 𝐶))
27	26	anbi2d 641	. . . . . . . . . . 11 ⊢ (𝑧 = 𝐶 → ((𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧) ↔ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶)))
28	25, 27	anbi12d 643	. . . . . . . . . 10 ⊢ (𝑧 = 𝐶 → ((({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)) ↔ (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶))))
29	28	rexbidv 3195	. . . . . . . . 9 ⊢ (𝑧 = 𝐶 → (∃𝑥 ∈ 𝑉 (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)) ↔ ∃𝑥 ∈ 𝑉 (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶))))
30	29	rspcv 3586	. . . . . . . 8 ⊢ (𝐶 ∈ (𝑉 ∖ {𝐴}) → (∀𝑧 ∈ (𝑉 ∖ {𝐴})∃𝑥 ∈ 𝑉 (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)) → ∃𝑥 ∈ 𝑉 (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶))))
31	10, 22, 30	sylsyld 62	. . . . . . 7 ⊢ (((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) ∧ 𝐴 ≠ 𝐶) → (∀𝑎 ∈ 𝑉 ∀𝑧 ∈ (𝑉 ∖ {𝑎})∃𝑥 ∈ 𝑉 (({𝑎, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝑎 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)) → ∃𝑥 ∈ 𝑉 (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶))))
32	1, 2	2pthfrgrrn 30574	. . . . . . . . . 10 ⊢ (𝐺 ∈ FriendGraph → ∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸))
33		necom 3017	. . . . . . . . . . . . . . . . . . . . . . . 24 ⊢ (𝐴 ≠ 𝑥 ↔ 𝑥 ≠ 𝐴)
34		eldifsn 4758	. . . . . . . . . . . . . . . . . . . . . . . . 25 ⊢ (𝑥 ∈ (𝑉 ∖ {𝐴}) ↔ (𝑥 ∈ 𝑉 ∧ 𝑥 ≠ 𝐴))
35	34	simplbi2com 507	. . . . . . . . . . . . . . . . . . . . . . . 24 ⊢ (𝑥 ≠ 𝐴 → (𝑥 ∈ 𝑉 → 𝑥 ∈ (𝑉 ∖ {𝐴})))
36	33, 35	sylbi 220	. . . . . . . . . . . . . . . . . . . . . . 23 ⊢ (𝐴 ≠ 𝑥 → (𝑥 ∈ 𝑉 → 𝑥 ∈ (𝑉 ∖ {𝐴})))
37	36	adantr 485	. . . . . . . . . . . . . . . . . . . . . 22 ⊢ ((𝐴 ≠ 𝑥 ∧ 𝐴 ∈ 𝑉) → (𝑥 ∈ 𝑉 → 𝑥 ∈ (𝑉 ∖ {𝐴})))
38	37	imp 411	. . . . . . . . . . . . . . . . . . . . 21 ⊢ (((𝐴 ≠ 𝑥 ∧ 𝐴 ∈ 𝑉) ∧ 𝑥 ∈ 𝑉) → 𝑥 ∈ (𝑉 ∖ {𝐴}))
39		sneq 4604	. . . . . . . . . . . . . . . . . . . . . . . . . 26 ⊢ (𝑢 = 𝐴 → {𝑢} = {𝐴})
40	39	difeq2d 4089	. . . . . . . . . . . . . . . . . . . . . . . . 25 ⊢ (𝑢 = 𝐴 → (𝑉 ∖ {𝑢}) = (𝑉 ∖ {𝐴}))
41		preq1 4704	. . . . . . . . . . . . . . . . . . . . . . . . . . . 28 ⊢ (𝑢 = 𝐴 → {𝑢, 𝑦} = {𝐴, 𝑦})
42	41	eleq1d 2854	. . . . . . . . . . . . . . . . . . . . . . . . . . 27 ⊢ (𝑢 = 𝐴 → ({𝑢, 𝑦} ∈ 𝐸 ↔ {𝐴, 𝑦} ∈ 𝐸))
43	42	anbi1d 642	. . . . . . . . . . . . . . . . . . . . . . . . . 26 ⊢ (𝑢 = 𝐴 → (({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) ↔ ({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸)))
44	43	rexbidv 3195	. . . . . . . . . . . . . . . . . . . . . . . . 25 ⊢ (𝑢 = 𝐴 → (∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) ↔ ∃𝑦 ∈ 𝑉 ({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸)))
45	40, 44	raleqbidv 3345	. . . . . . . . . . . . . . . . . . . . . . . 24 ⊢ (𝑢 = 𝐴 → (∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) ↔ ∀𝑣 ∈ (𝑉 ∖ {𝐴})∃𝑦 ∈ 𝑉 ({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸)))
46	45	rspcv 3586	. . . . . . . . . . . . . . . . . . . . . . 23 ⊢ (𝐴 ∈ 𝑉 → (∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → ∀𝑣 ∈ (𝑉 ∖ {𝐴})∃𝑦 ∈ 𝑉 ({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸)))
47	46	adantl 486	. . . . . . . . . . . . . . . . . . . . . 22 ⊢ ((𝐴 ≠ 𝑥 ∧ 𝐴 ∈ 𝑉) → (∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → ∀𝑣 ∈ (𝑉 ∖ {𝐴})∃𝑦 ∈ 𝑉 ({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸)))
48	47	adantr 485	. . . . . . . . . . . . . . . . . . . . 21 ⊢ (((𝐴 ≠ 𝑥 ∧ 𝐴 ∈ 𝑉) ∧ 𝑥 ∈ 𝑉) → (∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → ∀𝑣 ∈ (𝑉 ∖ {𝐴})∃𝑦 ∈ 𝑉 ({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸)))
49		preq2 4705	. . . . . . . . . . . . . . . . . . . . . . . . 25 ⊢ (𝑣 = 𝑥 → {𝑦, 𝑣} = {𝑦, 𝑥})
50	49	eleq1d 2854	. . . . . . . . . . . . . . . . . . . . . . . 24 ⊢ (𝑣 = 𝑥 → ({𝑦, 𝑣} ∈ 𝐸 ↔ {𝑦, 𝑥} ∈ 𝐸))
51	50	anbi2d 641	. . . . . . . . . . . . . . . . . . . . . . 23 ⊢ (𝑣 = 𝑥 → (({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) ↔ ({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑥} ∈ 𝐸)))
52	51	rexbidv 3195	. . . . . . . . . . . . . . . . . . . . . 22 ⊢ (𝑣 = 𝑥 → (∃𝑦 ∈ 𝑉 ({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) ↔ ∃𝑦 ∈ 𝑉 ({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑥} ∈ 𝐸)))
53	52	rspcv 3586	. . . . . . . . . . . . . . . . . . . . 21 ⊢ (𝑥 ∈ (𝑉 ∖ {𝐴}) → (∀𝑣 ∈ (𝑉 ∖ {𝐴})∃𝑦 ∈ 𝑉 ({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → ∃𝑦 ∈ 𝑉 ({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑥} ∈ 𝐸)))
54	38, 48, 53	sylsyld 62	. . . . . . . . . . . . . . . . . . . 20 ⊢ (((𝐴 ≠ 𝑥 ∧ 𝐴 ∈ 𝑉) ∧ 𝑥 ∈ 𝑉) → (∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → ∃𝑦 ∈ 𝑉 ({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑥} ∈ 𝐸)))
55		prcom 4703	. . . . . . . . . . . . . . . . . . . . . . . . . . 27 ⊢ {𝐴, 𝑦} = {𝑦, 𝐴}
56	55	eleq1i 2860	. . . . . . . . . . . . . . . . . . . . . . . . . 26 ⊢ ({𝐴, 𝑦} ∈ 𝐸 ↔ {𝑦, 𝐴} ∈ 𝐸)
57		prcom 4703	. . . . . . . . . . . . . . . . . . . . . . . . . . 27 ⊢ {𝑦, 𝑥} = {𝑥, 𝑦}
58	57	eleq1i 2860	. . . . . . . . . . . . . . . . . . . . . . . . . 26 ⊢ ({𝑦, 𝑥} ∈ 𝐸 ↔ {𝑥, 𝑦} ∈ 𝐸)
59	56, 58	anbi12ci 640	. . . . . . . . . . . . . . . . . . . . . . . . 25 ⊢ (({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑥} ∈ 𝐸) ↔ ({𝑥, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝐴} ∈ 𝐸))
60		preq2 4705	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 ⊢ (𝑏 = 𝑥 → {𝐴, 𝑏} = {𝐴, 𝑥})
61	60	eleq1d 2854	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 ⊢ (𝑏 = 𝑥 → ({𝐴, 𝑏} ∈ 𝐸 ↔ {𝐴, 𝑥} ∈ 𝐸))
62		preq1 4704	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 ⊢ (𝑏 = 𝑥 → {𝑏, 𝑐} = {𝑥, 𝑐})
63	62	eleq1d 2854	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 ⊢ (𝑏 = 𝑥 → ({𝑏, 𝑐} ∈ 𝐸 ↔ {𝑥, 𝑐} ∈ 𝐸))
64		biidd 265	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 ⊢ (𝑏 = 𝑥 → ({𝑐, 𝐴} ∈ 𝐸 ↔ {𝑐, 𝐴} ∈ 𝐸))
65	61, 63, 64	3anbi123d 1462	. . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 ⊢ (𝑏 = 𝑥 → (({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸) ↔ ({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))
66		biidd 265	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 ⊢ (𝑐 = 𝑦 → ({𝐴, 𝑥} ∈ 𝐸 ↔ {𝐴, 𝑥} ∈ 𝐸))
67		preq2 4705	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 ⊢ (𝑐 = 𝑦 → {𝑥, 𝑐} = {𝑥, 𝑦})
68	67	eleq1d 2854	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 ⊢ (𝑐 = 𝑦 → ({𝑥, 𝑐} ∈ 𝐸 ↔ {𝑥, 𝑦} ∈ 𝐸))
69		preq1 4704	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 ⊢ (𝑐 = 𝑦 → {𝑐, 𝐴} = {𝑦, 𝐴})
70	69	eleq1d 2854	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 ⊢ (𝑐 = 𝑦 → ({𝑐, 𝐴} ∈ 𝐸 ↔ {𝑦, 𝐴} ∈ 𝐸))
71	66, 68, 70	3anbi123d 1462	. . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 ⊢ (𝑐 = 𝑦 → (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸) ↔ ({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝐴} ∈ 𝐸)))
72	65, 71	rspc2ev 3603	. . . . . . . . . . . . . . . . . . . . . . . . . . . 28 ⊢ ((𝑥 ∈ 𝑉 ∧ 𝑦 ∈ 𝑉 ∧ ({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝐴} ∈ 𝐸)) → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))
73	72	3expa 1134	. . . . . . . . . . . . . . . . . . . . . . . . . . 27 ⊢ (((𝑥 ∈ 𝑉 ∧ 𝑦 ∈ 𝑉) ∧ ({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝐴} ∈ 𝐸)) → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))
74	73	expcom 418	. . . . . . . . . . . . . . . . . . . . . . . . . 26 ⊢ (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝐴} ∈ 𝐸) → ((𝑥 ∈ 𝑉 ∧ 𝑦 ∈ 𝑉) → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))
75	74	3expib 1138	. . . . . . . . . . . . . . . . . . . . . . . . 25 ⊢ ({𝐴, 𝑥} ∈ 𝐸 → (({𝑥, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝐴} ∈ 𝐸) → ((𝑥 ∈ 𝑉 ∧ 𝑦 ∈ 𝑉) → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))))
76	59, 75	biimtrid 245	. . . . . . . . . . . . . . . . . . . . . . . 24 ⊢ ({𝐴, 𝑥} ∈ 𝐸 → (({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑥} ∈ 𝐸) → ((𝑥 ∈ 𝑉 ∧ 𝑦 ∈ 𝑉) → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))))
77	76	adantr 485	. . . . . . . . . . . . . . . . . . . . . . 23 ⊢ (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) → (({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑥} ∈ 𝐸) → ((𝑥 ∈ 𝑉 ∧ 𝑦 ∈ 𝑉) → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))))
78	77	com13 89	. . . . . . . . . . . . . . . . . . . . . 22 ⊢ ((𝑥 ∈ 𝑉 ∧ 𝑦 ∈ 𝑉) → (({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑥} ∈ 𝐸) → (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))))
79	78	rexlimdva 3172	. . . . . . . . . . . . . . . . . . . . 21 ⊢ (𝑥 ∈ 𝑉 → (∃𝑦 ∈ 𝑉 ({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑥} ∈ 𝐸) → (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))))
80	79	com13 89	. . . . . . . . . . . . . . . . . . . 20 ⊢ (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) → (∃𝑦 ∈ 𝑉 ({𝐴, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑥} ∈ 𝐸) → (𝑥 ∈ 𝑉 → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))))
81	54, 80	syl9 78	. . . . . . . . . . . . . . . . . . 19 ⊢ (((𝐴 ≠ 𝑥 ∧ 𝐴 ∈ 𝑉) ∧ 𝑥 ∈ 𝑉) → (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) → (∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → (𝑥 ∈ 𝑉 → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))))
82	81	exp31 424	. . . . . . . . . . . . . . . . . 18 ⊢ (𝐴 ≠ 𝑥 → (𝐴 ∈ 𝑉 → (𝑥 ∈ 𝑉 → (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) → (∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → (𝑥 ∈ 𝑉 → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))))))
83	82	com24 96	. . . . . . . . . . . . . . . . 17 ⊢ (𝐴 ≠ 𝑥 → (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) → (𝑥 ∈ 𝑉 → (𝐴 ∈ 𝑉 → (∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → (𝑥 ∈ 𝑉 → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))))))
84	83	adantr 485	. . . . . . . . . . . . . . . 16 ⊢ ((𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶) → (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) → (𝑥 ∈ 𝑉 → (𝐴 ∈ 𝑉 → (∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → (𝑥 ∈ 𝑉 → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))))))
85	84	impcom 412	. . . . . . . . . . . . . . 15 ⊢ ((({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶)) → (𝑥 ∈ 𝑉 → (𝐴 ∈ 𝑉 → (∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → (𝑥 ∈ 𝑉 → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))))))
86	85	com15 102	. . . . . . . . . . . . . 14 ⊢ (𝑥 ∈ 𝑉 → (𝑥 ∈ 𝑉 → (𝐴 ∈ 𝑉 → (∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → ((({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶)) → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))))))
87	86	pm2.43i 53	. . . . . . . . . . . . 13 ⊢ (𝑥 ∈ 𝑉 → (𝐴 ∈ 𝑉 → (∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → ((({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶)) → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))))
88	87	com12 33	. . . . . . . . . . . 12 ⊢ (𝐴 ∈ 𝑉 → (𝑥 ∈ 𝑉 → (∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → ((({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶)) → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))))
89	88	ad2antrr 738	. . . . . . . . . . 11 ⊢ (((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) ∧ 𝐴 ≠ 𝐶) → (𝑥 ∈ 𝑉 → (∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → ((({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶)) → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))))
90	89	com4t 94	. . . . . . . . . 10 ⊢ (∀𝑢 ∈ 𝑉 ∀𝑣 ∈ (𝑉 ∖ {𝑢})∃𝑦 ∈ 𝑉 ({𝑢, 𝑦} ∈ 𝐸 ∧ {𝑦, 𝑣} ∈ 𝐸) → ((({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶)) → (((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) ∧ 𝐴 ≠ 𝐶) → (𝑥 ∈ 𝑉 → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))))
91	32, 90	syl 18	. . . . . . . . 9 ⊢ (𝐺 ∈ FriendGraph → ((({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶)) → (((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) ∧ 𝐴 ≠ 𝐶) → (𝑥 ∈ 𝑉 → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))))
92	91	com14 97	. . . . . . . 8 ⊢ (𝑥 ∈ 𝑉 → ((({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶)) → (((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) ∧ 𝐴 ≠ 𝐶) → (𝐺 ∈ FriendGraph → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))))
93	92	rexlimiv 3165	. . . . . . 7 ⊢ (∃𝑥 ∈ 𝑉 (({𝐴, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝐶} ∈ 𝐸) ∧ (𝐴 ≠ 𝑥 ∧ 𝑥 ≠ 𝐶)) → (((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) ∧ 𝐴 ≠ 𝐶) → (𝐺 ∈ FriendGraph → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))))
94	31, 93	syl6 36	. . . . . 6 ⊢ (((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) ∧ 𝐴 ≠ 𝐶) → (∀𝑎 ∈ 𝑉 ∀𝑧 ∈ (𝑉 ∖ {𝑎})∃𝑥 ∈ 𝑉 (({𝑎, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝑎 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)) → (((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) ∧ 𝐴 ≠ 𝐶) → (𝐺 ∈ FriendGraph → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))))
95	94	pm2.43a 55	. . . . 5 ⊢ (((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) ∧ 𝐴 ≠ 𝐶) → (∀𝑎 ∈ 𝑉 ∀𝑧 ∈ (𝑉 ∖ {𝑎})∃𝑥 ∈ 𝑉 (({𝑎, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝑎 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)) → (𝐺 ∈ FriendGraph → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))))
96	95	ex 417	. . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) → (𝐴 ≠ 𝐶 → (∀𝑎 ∈ 𝑉 ∀𝑧 ∈ (𝑉 ∖ {𝑎})∃𝑥 ∈ 𝑉 (({𝑎, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝑎 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)) → (𝐺 ∈ FriendGraph → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))))
97	96	com4t 94	. . 3 ⊢ (∀𝑎 ∈ 𝑉 ∀𝑧 ∈ (𝑉 ∖ {𝑎})∃𝑥 ∈ 𝑉 (({𝑎, 𝑥} ∈ 𝐸 ∧ {𝑥, 𝑧} ∈ 𝐸) ∧ (𝑎 ≠ 𝑥 ∧ 𝑥 ≠ 𝑧)) → (𝐺 ∈ FriendGraph → ((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) → (𝐴 ≠ 𝐶 → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸)))))
98	3, 97	mpcom 39	. 2 ⊢ (𝐺 ∈ FriendGraph → ((𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) → (𝐴 ≠ 𝐶 → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))))
99	98	3imp 1126	1 ⊢ ((𝐺 ∈ FriendGraph ∧ (𝐴 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉) ∧ 𝐴 ≠ 𝐶) → ∃𝑏 ∈ 𝑉 ∃𝑐 ∈ 𝑉 ({𝐴, 𝑏} ∈ 𝐸 ∧ {𝑏, 𝑐} ∈ 𝐸 ∧ {𝑐, 𝐴} ∈ 𝐸))

Colors of variables: wff setvar class

Syntax hints: → wi 4 ∧ wa 400 ∧ w3a 1101 = wceq 1567 ∈ wcel 2149 ≠ wne 2964 ∀wral 3085 ∃wrex 3095 ∖ cdif 3910 {csn 4594 {cpr 4596 ‘cfv 6537 Vtxcvtx 29287 Edgcedg 29338 FriendGraph cfrgr 30550

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1822 ax-4 1836 ax-5 1937 ax-6 1994 ax-7 2035 ax-8 2151 ax-9 2159 ax-10 2182 ax-11 2198 ax-12 2219 ax-ext 2741 ax-sep 5261 ax-nul 5271 ax-pow 5337 ax-pr 5405 ax-un 7733 ax-cnex 11156 ax-resscn 11157 ax-1cn 11158 ax-icn 11159 ax-addcl 11160 ax-addrcl 11161 ax-mulcl 11162 ax-mulrcl 11163 ax-mulcom 11164 ax-addass 11165 ax-mulass 11166 ax-distr 11167 ax-i2m1 11168 ax-1ne0 11169 ax-1rid 11170 ax-rnegex 11171 ax-rrecex 11172 ax-cnre 11173 ax-pre-lttri 11174 ax-pre-lttrn 11175 ax-pre-ltadd 11176 ax-pre-mulgt0 11177

This theorem depends on definitions: df-bi 210 df-an 401 df-or 861 df-3or 1102 df-3an 1103 df-tru 1570 df-fal 1580 df-ex 1807 df-nf 1811 df-sb 2098 df-mo 2573 df-eu 2603 df-clab 2748 df-cleq 2761 df-clel 2844 df-nfc 2918 df-ne 2965 df-nel 3071 df-ral 3086 df-rex 3096 df-rmo 3376 df-reu 3377 df-rab 3424 df-v 3465 df-sbc 3754 df-csb 3862 df-dif 3916 df-un 3918 df-in 3920 df-ss 3930 df-pss 3933 df-nul 4295 df-if 4493 df-pw 4569 df-sn 4595 df-pr 4597 df-op 4601 df-uni 4877 df-int 4917 df-iun 4962 df-br 5114 df-opab 5178 df-mpt 5197 df-tr 5223 df-id 5557 df-eprel 5562 df-po 5570 df-so 5571 df-fr 5615 df-we 5617 df-xp 5668 df-rel 5669 df-cnv 5670 df-co 5671 df-dm 5672 df-rn 5673 df-res 5674 df-ima 5675 df-pred 6303 df-ord 6364 df-on 6365 df-lim 6366 df-suc 6367 df-iota 6493 df-fun 6539 df-fn 6540 df-f 6541 df-f1 6542 df-fo 6543 df-f1o 6544 df-fv 6545 df-riota 7368 df-ov 7414 df-oprab 7415 df-mpo 7416 df-om 7863 df-1st 7986 df-2nd 7987 df-frecs 8278 df-wrecs 8309 df-recs 8358 df-rdg 8397 df-1o 8453 df-oadd 8457 df-er 8694 df-en 8944 df-dom 8945 df-sdom 8946 df-fin 8947 df-dju 9887 df-card 9925 df-pnf 11245 df-mnf 11246 df-xr 11247 df-ltxr 11248 df-le 11249 df-sub 11443 df-neg 11444 df-nn 12234 df-2 12303 df-n0 12505 df-z 12592 df-uz 12863 df-fz 13536 df-hash 14367 df-edg 29339 df-umgr 29374 df-usgr 29442 df-frgr 30551

This theorem is referenced by: 3cyclfrgrrn 30578

W3C validator