Theorem frgrncvvdeqlemC 41478

Description: Lemma C for frgrncvvdeq 41480. This corresponds to statement 3 in [Huneke] p. 1: "By symmetry the map is onto". (Contributed by Alexander van der Vekens, 24-Dec-2017.) (Revised by AV, 10-May-2021.)

Hypotheses

Ref	Expression
frgrncvvdeq.v1	⊢ 𝑉 = (Vtx‘𝐺)
frgrncvvdeq.e	⊢ 𝐸 = (Edg‘𝐺)
frgrncvvdeq.nx	⊢ 𝐷 = (𝐺 NeighbVtx 𝑋)
frgrncvvdeq.ny	⊢ 𝑁 = (𝐺 NeighbVtx 𝑌)
frgrncvvdeq.x	⊢ (𝜑 → 𝑋 ∈ 𝑉)
frgrncvvdeq.y	⊢ (𝜑 → 𝑌 ∈ 𝑉)
frgrncvvdeq.ne	⊢ (𝜑 → 𝑋 ≠ 𝑌)
frgrncvvdeq.xy	⊢ (𝜑 → 𝑌 ∉ 𝐷)
frgrncvvdeq.f	⊢ (𝜑 → 𝐺 ∈ FriendGraph )
frgrncvvdeq.a	⊢ 𝐴 = (𝑥 ∈ 𝐷 ↦ (℩𝑦 ∈ 𝑁 {𝑥, 𝑦} ∈ 𝐸))

Assertion

Ref	Expression
frgrncvvdeqlemC	⊢ (𝜑 → 𝐴:𝐷–onto→𝑁)

Distinct variable groups:   𝑦,𝐷   𝑦,𝐺   𝑦,𝑉   𝑦,𝑌   𝜑,𝑦,𝑥   𝑦,𝐸   𝑦,𝑁   𝑥,𝐷   𝑥,𝑁   𝜑,𝑥   𝑥,𝐸

Allowed substitution hints:   𝐴(𝑥,𝑦)   𝐺(𝑥)   𝑉(𝑥)   𝑋(𝑥,𝑦)   𝑌(𝑥)

Proof of Theorem frgrncvvdeqlemC

Dummy variables 𝑛 𝑚 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		frgrncvvdeq.v1	. . 3 ⊢ 𝑉 = (Vtx‘𝐺)
2		frgrncvvdeq.e	. . 3 ⊢ 𝐸 = (Edg‘𝐺)
3		frgrncvvdeq.nx	. . 3 ⊢ 𝐷 = (𝐺 NeighbVtx 𝑋)
4		frgrncvvdeq.ny	. . 3 ⊢ 𝑁 = (𝐺 NeighbVtx 𝑌)
5		frgrncvvdeq.x	. . 3 ⊢ (𝜑 → 𝑋 ∈ 𝑉)
6		frgrncvvdeq.y	. . 3 ⊢ (𝜑 → 𝑌 ∈ 𝑉)
7		frgrncvvdeq.ne	. . 3 ⊢ (𝜑 → 𝑋 ≠ 𝑌)
8		frgrncvvdeq.xy	. . 3 ⊢ (𝜑 → 𝑌 ∉ 𝐷)
9		frgrncvvdeq.f	. . 3 ⊢ (𝜑 → 𝐺 ∈ FriendGraph )
10		frgrncvvdeq.a	. . 3 ⊢ 𝐴 = (𝑥 ∈ 𝐷 ↦ (℩𝑦 ∈ 𝑁 {𝑥, 𝑦} ∈ 𝐸))
11	1, 2, 3, 4, 5, 6, 7, 8, 9, 10	frgrncvvdeqlem5 41473	. 2 ⊢ (𝜑 → 𝐴:𝐷⟶𝑁)
12	9	adantr 480	. . . . . . 7 ⊢ ((𝜑 ∧ 𝑛 ∈ 𝑁) → 𝐺 ∈ FriendGraph )
13	4	eleq2i 2680	. . . . . . . . . 10 ⊢ (𝑛 ∈ 𝑁 ↔ 𝑛 ∈ (𝐺 NeighbVtx 𝑌))
14		frgrusgr 41432	. . . . . . . . . . 11 ⊢ (𝐺 ∈ FriendGraph → 𝐺 ∈ USGraph )
15	1	nbgrisvtx 40581	. . . . . . . . . . . 12 ⊢ ((𝐺 ∈ USGraph ∧ 𝑛 ∈ (𝐺 NeighbVtx 𝑌)) → 𝑛 ∈ 𝑉)
16	15	ex 449	. . . . . . . . . . 11 ⊢ (𝐺 ∈ USGraph → (𝑛 ∈ (𝐺 NeighbVtx 𝑌) → 𝑛 ∈ 𝑉))
17	9, 14, 16	3syl 18	. . . . . . . . . 10 ⊢ (𝜑 → (𝑛 ∈ (𝐺 NeighbVtx 𝑌) → 𝑛 ∈ 𝑉))
18	13, 17	syl5bi 231	. . . . . . . . 9 ⊢ (𝜑 → (𝑛 ∈ 𝑁 → 𝑛 ∈ 𝑉))
19	18	imp 444	. . . . . . . 8 ⊢ ((𝜑 ∧ 𝑛 ∈ 𝑁) → 𝑛 ∈ 𝑉)
20	5	adantr 480	. . . . . . . 8 ⊢ ((𝜑 ∧ 𝑛 ∈ 𝑁) → 𝑋 ∈ 𝑉)
21	1, 2, 3, 4, 5, 6, 7, 8, 9, 10	frgrncvvdeqlem2 41470	. . . . . . . . . 10 ⊢ (𝜑 → 𝑋 ∉ 𝑁)
22		df-nel 2783	. . . . . . . . . . 11 ⊢ (𝑋 ∉ 𝑁 ↔ ¬ 𝑋 ∈ 𝑁)
23		nelelne 2880	. . . . . . . . . . 11 ⊢ (¬ 𝑋 ∈ 𝑁 → (𝑛 ∈ 𝑁 → 𝑛 ≠ 𝑋))
24	22, 23	sylbi 206	. . . . . . . . . 10 ⊢ (𝑋 ∉ 𝑁 → (𝑛 ∈ 𝑁 → 𝑛 ≠ 𝑋))
25	21, 24	syl 17	. . . . . . . . 9 ⊢ (𝜑 → (𝑛 ∈ 𝑁 → 𝑛 ≠ 𝑋))
26	25	imp 444	. . . . . . . 8 ⊢ ((𝜑 ∧ 𝑛 ∈ 𝑁) → 𝑛 ≠ 𝑋)
27	19, 20, 26	3jca 1235	. . . . . . 7 ⊢ ((𝜑 ∧ 𝑛 ∈ 𝑁) → (𝑛 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉 ∧ 𝑛 ≠ 𝑋))
28	12, 27	jca 553	. . . . . 6 ⊢ ((𝜑 ∧ 𝑛 ∈ 𝑁) → (𝐺 ∈ FriendGraph ∧ (𝑛 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉 ∧ 𝑛 ≠ 𝑋)))
29	1, 2	frcond2 41439	. . . . . . 7 ⊢ (𝐺 ∈ FriendGraph → ((𝑛 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉 ∧ 𝑛 ≠ 𝑋) → ∃!𝑚 ∈ 𝑉 ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)))
30	29	imp 444	. . . . . 6 ⊢ ((𝐺 ∈ FriendGraph ∧ (𝑛 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉 ∧ 𝑛 ≠ 𝑋)) → ∃!𝑚 ∈ 𝑉 ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸))
31		reurex 3137	. . . . . . 7 ⊢ (∃!𝑚 ∈ 𝑉 ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸) → ∃𝑚 ∈ 𝑉 ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸))
32		df-rex 2902	. . . . . . 7 ⊢ (∃𝑚 ∈ 𝑉 ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸) ↔ ∃𝑚(𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)))
33	31, 32	sylib 207	. . . . . 6 ⊢ (∃!𝑚 ∈ 𝑉 ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸) → ∃𝑚(𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)))
34	28, 30, 33	3syl 18	. . . . 5 ⊢ ((𝜑 ∧ 𝑛 ∈ 𝑁) → ∃𝑚(𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)))
35	9, 14	syl 17	. . . . . . . 8 ⊢ (𝜑 → 𝐺 ∈ USGraph )
36		simprrr 801	. . . . . . . . . . 11 ⊢ ((((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ 𝑛 ∈ 𝑁) ∧ (𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸))) → {𝑚, 𝑋} ∈ 𝐸)
37	3	eleq2i 2680	. . . . . . . . . . . 12 ⊢ (𝑚 ∈ 𝐷 ↔ 𝑚 ∈ (𝐺 NeighbVtx 𝑋))
38	2	nbusgreledg 40575	. . . . . . . . . . . . . 14 ⊢ (𝐺 ∈ USGraph → (𝑚 ∈ (𝐺 NeighbVtx 𝑋) ↔ {𝑚, 𝑋} ∈ 𝐸))
39	38	ad2antlr 759	. . . . . . . . . . . . 13 ⊢ (((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ 𝑛 ∈ 𝑁) → (𝑚 ∈ (𝐺 NeighbVtx 𝑋) ↔ {𝑚, 𝑋} ∈ 𝐸))
40	39	adantr 480	. . . . . . . . . . . 12 ⊢ ((((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ 𝑛 ∈ 𝑁) ∧ (𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸))) → (𝑚 ∈ (𝐺 NeighbVtx 𝑋) ↔ {𝑚, 𝑋} ∈ 𝐸))
41	37, 40	syl5bb 271	. . . . . . . . . . 11 ⊢ ((((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ 𝑛 ∈ 𝑁) ∧ (𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸))) → (𝑚 ∈ 𝐷 ↔ {𝑚, 𝑋} ∈ 𝐸))
42	36, 41	mpbird 246	. . . . . . . . . 10 ⊢ ((((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ 𝑛 ∈ 𝑁) ∧ (𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸))) → 𝑚 ∈ 𝐷)
43	2	nbusgreledg 40575	. . . . . . . . . . . . . . . . 17 ⊢ (𝐺 ∈ USGraph → (𝑛 ∈ (𝐺 NeighbVtx 𝑚) ↔ {𝑛, 𝑚} ∈ 𝐸))
44	43	biimprcd 239	. . . . . . . . . . . . . . . 16 ⊢ ({𝑛, 𝑚} ∈ 𝐸 → (𝐺 ∈ USGraph → 𝑛 ∈ (𝐺 NeighbVtx 𝑚)))
45	44	adantr 480	. . . . . . . . . . . . . . 15 ⊢ (({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸) → (𝐺 ∈ USGraph → 𝑛 ∈ (𝐺 NeighbVtx 𝑚)))
46	45	adantl 481	. . . . . . . . . . . . . 14 ⊢ ((𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)) → (𝐺 ∈ USGraph → 𝑛 ∈ (𝐺 NeighbVtx 𝑚)))
47	46	com12 32	. . . . . . . . . . . . 13 ⊢ (𝐺 ∈ USGraph → ((𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)) → 𝑛 ∈ (𝐺 NeighbVtx 𝑚)))
48	47	ad2antlr 759	. . . . . . . . . . . 12 ⊢ (((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ 𝑛 ∈ 𝑁) → ((𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)) → 𝑛 ∈ (𝐺 NeighbVtx 𝑚)))
49	48	imp 444	. . . . . . . . . . 11 ⊢ ((((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ 𝑛 ∈ 𝑁) ∧ (𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸))) → 𝑛 ∈ (𝐺 NeighbVtx 𝑚))
50		elin 3758	. . . . . . . . . . . . . . 15 ⊢ (𝑛 ∈ ((𝐺 NeighbVtx 𝑚) ∩ 𝑁) ↔ (𝑛 ∈ (𝐺 NeighbVtx 𝑚) ∧ 𝑛 ∈ 𝑁))
51		simpll 786	. . . . . . . . . . . . . . . . . . . 20 ⊢ (((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ {𝑚, 𝑋} ∈ 𝐸) → 𝜑)
52	38	bicomd 212	. . . . . . . . . . . . . . . . . . . . . . 23 ⊢ (𝐺 ∈ USGraph → ({𝑚, 𝑋} ∈ 𝐸 ↔ 𝑚 ∈ (𝐺 NeighbVtx 𝑋)))
53	52	adantl 481	. . . . . . . . . . . . . . . . . . . . . 22 ⊢ ((𝜑 ∧ 𝐺 ∈ USGraph ) → ({𝑚, 𝑋} ∈ 𝐸 ↔ 𝑚 ∈ (𝐺 NeighbVtx 𝑋)))
54	53	biimpa 500	. . . . . . . . . . . . . . . . . . . . 21 ⊢ (((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ {𝑚, 𝑋} ∈ 𝐸) → 𝑚 ∈ (𝐺 NeighbVtx 𝑋))
55	54, 37	sylibr 223	. . . . . . . . . . . . . . . . . . . 20 ⊢ (((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ {𝑚, 𝑋} ∈ 𝐸) → 𝑚 ∈ 𝐷)
56	51, 55	jca 553	. . . . . . . . . . . . . . . . . . 19 ⊢ (((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ {𝑚, 𝑋} ∈ 𝐸) → (𝜑 ∧ 𝑚 ∈ 𝐷))
57		preq1 4212	. . . . . . . . . . . . . . . . . . . . . . . 24 ⊢ (𝑥 = 𝑚 → {𝑥, 𝑦} = {𝑚, 𝑦})
58	57	eleq1d 2672	. . . . . . . . . . . . . . . . . . . . . . 23 ⊢ (𝑥 = 𝑚 → ({𝑥, 𝑦} ∈ 𝐸 ↔ {𝑚, 𝑦} ∈ 𝐸))
59	58	riotabidv 6513	. . . . . . . . . . . . . . . . . . . . . 22 ⊢ (𝑥 = 𝑚 → (℩𝑦 ∈ 𝑁 {𝑥, 𝑦} ∈ 𝐸) = (℩𝑦 ∈ 𝑁 {𝑚, 𝑦} ∈ 𝐸))
60	59	cbvmptv 4678	. . . . . . . . . . . . . . . . . . . . 21 ⊢ (𝑥 ∈ 𝐷 ↦ (℩𝑦 ∈ 𝑁 {𝑥, 𝑦} ∈ 𝐸)) = (𝑚 ∈ 𝐷 ↦ (℩𝑦 ∈ 𝑁 {𝑚, 𝑦} ∈ 𝐸))
61	10, 60	eqtri 2632	. . . . . . . . . . . . . . . . . . . 20 ⊢ 𝐴 = (𝑚 ∈ 𝐷 ↦ (℩𝑦 ∈ 𝑁 {𝑚, 𝑦} ∈ 𝐸))
62	1, 2, 3, 4, 5, 6, 7, 8, 9, 61	frgrncvvdeqlem6 41474	. . . . . . . . . . . . . . . . . . 19 ⊢ ((𝜑 ∧ 𝑚 ∈ 𝐷) → {(𝐴‘𝑚)} = ((𝐺 NeighbVtx 𝑚) ∩ 𝑁))
63		eleq2 2677	. . . . . . . . . . . . . . . . . . . . 21 ⊢ (((𝐺 NeighbVtx 𝑚) ∩ 𝑁) = {(𝐴‘𝑚)} → (𝑛 ∈ ((𝐺 NeighbVtx 𝑚) ∩ 𝑁) ↔ 𝑛 ∈ {(𝐴‘𝑚)}))
64	63	eqcoms 2618	. . . . . . . . . . . . . . . . . . . 20 ⊢ ({(𝐴‘𝑚)} = ((𝐺 NeighbVtx 𝑚) ∩ 𝑁) → (𝑛 ∈ ((𝐺 NeighbVtx 𝑚) ∩ 𝑁) ↔ 𝑛 ∈ {(𝐴‘𝑚)}))
65		elsni 4142	. . . . . . . . . . . . . . . . . . . 20 ⊢ (𝑛 ∈ {(𝐴‘𝑚)} → 𝑛 = (𝐴‘𝑚))
66	64, 65	syl6bi 242	. . . . . . . . . . . . . . . . . . 19 ⊢ ({(𝐴‘𝑚)} = ((𝐺 NeighbVtx 𝑚) ∩ 𝑁) → (𝑛 ∈ ((𝐺 NeighbVtx 𝑚) ∩ 𝑁) → 𝑛 = (𝐴‘𝑚)))
67	56, 62, 66	3syl 18	. . . . . . . . . . . . . . . . . 18 ⊢ (((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ {𝑚, 𝑋} ∈ 𝐸) → (𝑛 ∈ ((𝐺 NeighbVtx 𝑚) ∩ 𝑁) → 𝑛 = (𝐴‘𝑚)))
68	67	expcom 450	. . . . . . . . . . . . . . . . 17 ⊢ ({𝑚, 𝑋} ∈ 𝐸 → ((𝜑 ∧ 𝐺 ∈ USGraph ) → (𝑛 ∈ ((𝐺 NeighbVtx 𝑚) ∩ 𝑁) → 𝑛 = (𝐴‘𝑚))))
69	68	ad2antll 761	. . . . . . . . . . . . . . . 16 ⊢ ((𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)) → ((𝜑 ∧ 𝐺 ∈ USGraph ) → (𝑛 ∈ ((𝐺 NeighbVtx 𝑚) ∩ 𝑁) → 𝑛 = (𝐴‘𝑚))))
70	69	com3r 85	. . . . . . . . . . . . . . 15 ⊢ (𝑛 ∈ ((𝐺 NeighbVtx 𝑚) ∩ 𝑁) → ((𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)) → ((𝜑 ∧ 𝐺 ∈ USGraph ) → 𝑛 = (𝐴‘𝑚))))
71	50, 70	sylbir 224	. . . . . . . . . . . . . 14 ⊢ ((𝑛 ∈ (𝐺 NeighbVtx 𝑚) ∧ 𝑛 ∈ 𝑁) → ((𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)) → ((𝜑 ∧ 𝐺 ∈ USGraph ) → 𝑛 = (𝐴‘𝑚))))
72	71	ex 449	. . . . . . . . . . . . 13 ⊢ (𝑛 ∈ (𝐺 NeighbVtx 𝑚) → (𝑛 ∈ 𝑁 → ((𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)) → ((𝜑 ∧ 𝐺 ∈ USGraph ) → 𝑛 = (𝐴‘𝑚)))))
73	72	com14 94	. . . . . . . . . . . 12 ⊢ ((𝜑 ∧ 𝐺 ∈ USGraph ) → (𝑛 ∈ 𝑁 → ((𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)) → (𝑛 ∈ (𝐺 NeighbVtx 𝑚) → 𝑛 = (𝐴‘𝑚)))))
74	73	imp31 447	. . . . . . . . . . 11 ⊢ ((((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ 𝑛 ∈ 𝑁) ∧ (𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸))) → (𝑛 ∈ (𝐺 NeighbVtx 𝑚) → 𝑛 = (𝐴‘𝑚)))
75	49, 74	mpd 15	. . . . . . . . . 10 ⊢ ((((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ 𝑛 ∈ 𝑁) ∧ (𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸))) → 𝑛 = (𝐴‘𝑚))
76	42, 75	jca 553	. . . . . . . . 9 ⊢ ((((𝜑 ∧ 𝐺 ∈ USGraph ) ∧ 𝑛 ∈ 𝑁) ∧ (𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸))) → (𝑚 ∈ 𝐷 ∧ 𝑛 = (𝐴‘𝑚)))
77	76	exp31 628	. . . . . . . 8 ⊢ ((𝜑 ∧ 𝐺 ∈ USGraph ) → (𝑛 ∈ 𝑁 → ((𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)) → (𝑚 ∈ 𝐷 ∧ 𝑛 = (𝐴‘𝑚)))))
78	35, 77	mpdan 699	. . . . . . 7 ⊢ (𝜑 → (𝑛 ∈ 𝑁 → ((𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)) → (𝑚 ∈ 𝐷 ∧ 𝑛 = (𝐴‘𝑚)))))
79	78	imp 444	. . . . . 6 ⊢ ((𝜑 ∧ 𝑛 ∈ 𝑁) → ((𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)) → (𝑚 ∈ 𝐷 ∧ 𝑛 = (𝐴‘𝑚))))
80	79	eximdv 1833	. . . . 5 ⊢ ((𝜑 ∧ 𝑛 ∈ 𝑁) → (∃𝑚(𝑚 ∈ 𝑉 ∧ ({𝑛, 𝑚} ∈ 𝐸 ∧ {𝑚, 𝑋} ∈ 𝐸)) → ∃𝑚(𝑚 ∈ 𝐷 ∧ 𝑛 = (𝐴‘𝑚))))
81	34, 80	mpd 15	. . . 4 ⊢ ((𝜑 ∧ 𝑛 ∈ 𝑁) → ∃𝑚(𝑚 ∈ 𝐷 ∧ 𝑛 = (𝐴‘𝑚)))
82		df-rex 2902	. . . 4 ⊢ (∃𝑚 ∈ 𝐷 𝑛 = (𝐴‘𝑚) ↔ ∃𝑚(𝑚 ∈ 𝐷 ∧ 𝑛 = (𝐴‘𝑚)))
83	81, 82	sylibr 223	. . 3 ⊢ ((𝜑 ∧ 𝑛 ∈ 𝑁) → ∃𝑚 ∈ 𝐷 𝑛 = (𝐴‘𝑚))
84	83	ralrimiva 2949	. 2 ⊢ (𝜑 → ∀𝑛 ∈ 𝑁 ∃𝑚 ∈ 𝐷 𝑛 = (𝐴‘𝑚))
85		dffo3 6282	. 2 ⊢ (𝐴:𝐷–onto→𝑁 ↔ (𝐴:𝐷⟶𝑁 ∧ ∀𝑛 ∈ 𝑁 ∃𝑚 ∈ 𝐷 𝑛 = (𝐴‘𝑚)))
86	11, 84, 85	sylanbrc 695	1 ⊢ (𝜑 → 𝐴:𝐷–onto→𝑁)

Syntax hints:  ¬ wn 3   → wi 4   ↔ wb 195   ∧ wa 383   ∧ w3a 1031   = wceq 1475  ∃wex 1695   ∈ wcel 1977   ≠ wne 2780   ∉ wnel 2781  ∀wral 2896  ∃wrex 2897  ∃!wreu 2898   ∩ cin 3539  {csn 4125  {cpr 4127   ↦ cmpt 4643  ⟶wf 5800  –onto→wfo 5802  ‘cfv 5804  ℩crio 6510  (class class class)co 6549  Vtxcvtx 25673  Edgcedga 25792   USGraph cusgr 40379   NeighbVtx cnbgr 40550   FriendGraph cfrgr 41428

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1713  ax-4 1728  ax-5 1827  ax-6 1875  ax-7 1922  ax-8 1979  ax-9 1986  ax-10 2006  ax-11 2021  ax-12 2034  ax-13 2234  ax-ext 2590  ax-rep 4699  ax-sep 4709  ax-nul 4717  ax-pow 4769  ax-pr 4833  ax-un 6847  ax-cnex 9871  ax-resscn 9872  ax-1cn 9873  ax-icn 9874  ax-addcl 9875  ax-addrcl 9876  ax-mulcl 9877  ax-mulrcl 9878  ax-mulcom 9879  ax-addass 9880  ax-mulass 9881  ax-distr 9882  ax-i2m1 9883  ax-1ne0 9884  ax-1rid 9885  ax-rnegex 9886  ax-rrecex 9887  ax-cnre 9888  ax-pre-lttri 9889  ax-pre-lttrn 9890  ax-pre-ltadd 9891  ax-pre-mulgt0 9892

This theorem depends on definitions:  df-bi 196  df-or 384  df-an 385  df-3or 1032  df-3an 1033  df-tru 1478  df-fal 1481  df-ex 1696  df-nf 1701  df-sb 1868  df-eu 2462  df-mo 2463  df-clab 2597  df-cleq 2603  df-clel 2606  df-nfc 2740  df-ne 2782  df-nel 2783  df-ral 2901  df-rex 2902  df-reu 2903  df-rmo 2904  df-rab 2905  df-v 3175  df-sbc 3403  df-csb 3500  df-dif 3543  df-un 3545  df-in 3547  df-ss 3554  df-pss 3556  df-nul 3875  df-if 4037  df-pw 4110  df-sn 4126  df-pr 4128  df-tp 4130  df-op 4132  df-uni 4373  df-int 4411  df-iun 4457  df-br 4584  df-opab 4644  df-mpt 4645  df-tr 4681  df-eprel 4949  df-id 4953  df-po 4959  df-so 4960  df-fr 4997  df-we 4999  df-xp 5044  df-rel 5045  df-cnv 5046  df-co 5047  df-dm 5048  df-rn 5049  df-res 5050  df-ima 5051  df-pred 5597  df-ord 5643  df-on 5644  df-lim 5645  df-suc 5646  df-iota 5768  df-fun 5806  df-fn 5807  df-f 5808  df-f1 5809  df-fo 5810  df-f1o 5811  df-fv 5812  df-riota 6511  df-ov 6552  df-oprab 6553  df-mpt2 6554  df-om 6958  df-1st 7059  df-2nd 7060  df-wrecs 7294  df-recs 7355  df-rdg 7393  df-1o 7447  df-2o 7448  df-oadd 7451  df-er 7629  df-en 7842  df-dom 7843  df-sdom 7844  df-fin 7845  df-card 8648  df-cda 8873  df-pnf 9955  df-mnf 9956  df-xr 9957  df-ltxr 9958  df-le 9959  df-sub 10147  df-neg 10148  df-nn 10898  df-2 10956  df-n0 11170  df-z 11255  df-uz 11564  df-fz 12198  df-hash 12980  df-upgr 25749  df-umgr 25750  df-edga 25793  df-usgr 40381  df-nbgr 40554  df-frgr 41429

This theorem is referenced by:  frgrncvvdeqlem8  41479