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Theorem dfclnbgr6 47459
Description: Alternate definition of the closed neighborhood of a vertex as union of the vertex with its semiopen neighborhood. (Contributed by AV, 17-May-2025.)
Hypotheses
Ref Expression
dfvopnbgr2.v 𝑉 = (Vtx‘𝐺)
dfvopnbgr2.e 𝐸 = (Edg‘𝐺)
dfvopnbgr2.u 𝑈 = {𝑛𝑉 ∣ (𝑛 ∈ (𝐺 NeighbVtx 𝑁) ∨ ∃𝑒𝐸 (𝑁 = 𝑛𝑒 = {𝑁}))}
Assertion
Ref Expression
dfclnbgr6 (𝑁𝑉 → (𝐺 ClNeighbVtx 𝑁) = ({𝑁} ∪ 𝑈))
Distinct variable groups:   𝑒,𝐸   𝑒,𝐺   𝑒,𝑁,𝑛   𝑒,𝑉,𝑛   𝑛,𝐸   𝑛,𝐺
Allowed substitution hints:   𝑈(𝑒,𝑛)

Proof of Theorem dfclnbgr6
Dummy variable 𝑣 is distinct from all other variables.
StepHypRef Expression
1 orc 865 . . . . . . 7 (𝑣 = 𝑁 → (𝑣 = 𝑁 ∨ ((𝑣𝑉 ∧ ∃𝑒𝐸 (𝑁𝑒𝑣𝑒)) ↔ (𝑣𝑉 ∧ ∃𝑒𝐸 ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣}))))))
21a1d 25 . . . . . 6 (𝑣 = 𝑁 → (𝑁𝑉 → (𝑣 = 𝑁 ∨ ((𝑣𝑉 ∧ ∃𝑒𝐸 (𝑁𝑒𝑣𝑒)) ↔ (𝑣𝑉 ∧ ∃𝑒𝐸 ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣})))))))
3 simpl 481 . . . . . . . . . . . . . . 15 ((𝑣𝑁𝑁𝑉) → 𝑣𝑁)
43anim1i 613 . . . . . . . . . . . . . 14 (((𝑣𝑁𝑁𝑉) ∧ (𝑁𝑒𝑣𝑒)) → (𝑣𝑁 ∧ (𝑁𝑒𝑣𝑒)))
5 3anass 1092 . . . . . . . . . . . . . 14 ((𝑣𝑁𝑁𝑒𝑣𝑒) ↔ (𝑣𝑁 ∧ (𝑁𝑒𝑣𝑒)))
64, 5sylibr 233 . . . . . . . . . . . . 13 (((𝑣𝑁𝑁𝑉) ∧ (𝑁𝑒𝑣𝑒)) → (𝑣𝑁𝑁𝑒𝑣𝑒))
76orcd 871 . . . . . . . . . . . 12 (((𝑣𝑁𝑁𝑉) ∧ (𝑁𝑒𝑣𝑒)) → ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣})))
87ex 411 . . . . . . . . . . 11 ((𝑣𝑁𝑁𝑉) → ((𝑁𝑒𝑣𝑒) → ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣}))))
9 3simpc 1147 . . . . . . . . . . . . 13 ((𝑣𝑁𝑁𝑒𝑣𝑒) → (𝑁𝑒𝑣𝑒))
109a1i 11 . . . . . . . . . . . 12 ((𝑣𝑁𝑁𝑉) → ((𝑣𝑁𝑁𝑒𝑣𝑒) → (𝑁𝑒𝑣𝑒)))
11 vsnid 4660 . . . . . . . . . . . . . . . . 17 𝑣 ∈ {𝑣}
12 eleq2 2815 . . . . . . . . . . . . . . . . 17 (𝑒 = {𝑣} → (𝑣𝑒𝑣 ∈ {𝑣}))
1311, 12mpbiri 257 . . . . . . . . . . . . . . . 16 (𝑒 = {𝑣} → 𝑣𝑒)
1413adantl 480 . . . . . . . . . . . . . . 15 ((𝑣 = 𝑁𝑒 = {𝑣}) → 𝑣𝑒)
15 eleq1 2814 . . . . . . . . . . . . . . . 16 (𝑣 = 𝑁 → (𝑣𝑒𝑁𝑒))
1615adantr 479 . . . . . . . . . . . . . . 15 ((𝑣 = 𝑁𝑒 = {𝑣}) → (𝑣𝑒𝑁𝑒))
1714, 16mpbid 231 . . . . . . . . . . . . . 14 ((𝑣 = 𝑁𝑒 = {𝑣}) → 𝑁𝑒)
1817, 14jca 510 . . . . . . . . . . . . 13 ((𝑣 = 𝑁𝑒 = {𝑣}) → (𝑁𝑒𝑣𝑒))
1918a1i 11 . . . . . . . . . . . 12 ((𝑣𝑁𝑁𝑉) → ((𝑣 = 𝑁𝑒 = {𝑣}) → (𝑁𝑒𝑣𝑒)))
2010, 19jaod 857 . . . . . . . . . . 11 ((𝑣𝑁𝑁𝑉) → (((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣})) → (𝑁𝑒𝑣𝑒)))
218, 20impbid 211 . . . . . . . . . 10 ((𝑣𝑁𝑁𝑉) → ((𝑁𝑒𝑣𝑒) ↔ ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣}))))
2221rexbidv 3169 . . . . . . . . 9 ((𝑣𝑁𝑁𝑉) → (∃𝑒𝐸 (𝑁𝑒𝑣𝑒) ↔ ∃𝑒𝐸 ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣}))))
2322anbi2d 628 . . . . . . . 8 ((𝑣𝑁𝑁𝑉) → ((𝑣𝑉 ∧ ∃𝑒𝐸 (𝑁𝑒𝑣𝑒)) ↔ (𝑣𝑉 ∧ ∃𝑒𝐸 ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣})))))
2423olcd 872 . . . . . . 7 ((𝑣𝑁𝑁𝑉) → (𝑣 = 𝑁 ∨ ((𝑣𝑉 ∧ ∃𝑒𝐸 (𝑁𝑒𝑣𝑒)) ↔ (𝑣𝑉 ∧ ∃𝑒𝐸 ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣}))))))
2524ex 411 . . . . . 6 (𝑣𝑁 → (𝑁𝑉 → (𝑣 = 𝑁 ∨ ((𝑣𝑉 ∧ ∃𝑒𝐸 (𝑁𝑒𝑣𝑒)) ↔ (𝑣𝑉 ∧ ∃𝑒𝐸 ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣})))))))
262, 25pm2.61ine 3015 . . . . 5 (𝑁𝑉 → (𝑣 = 𝑁 ∨ ((𝑣𝑉 ∧ ∃𝑒𝐸 (𝑁𝑒𝑣𝑒)) ↔ (𝑣𝑉 ∧ ∃𝑒𝐸 ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣}))))))
27 orbidi 950 . . . . 5 ((𝑣 = 𝑁 ∨ ((𝑣𝑉 ∧ ∃𝑒𝐸 (𝑁𝑒𝑣𝑒)) ↔ (𝑣𝑉 ∧ ∃𝑒𝐸 ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣}))))) ↔ ((𝑣 = 𝑁 ∨ (𝑣𝑉 ∧ ∃𝑒𝐸 (𝑁𝑒𝑣𝑒))) ↔ (𝑣 = 𝑁 ∨ (𝑣𝑉 ∧ ∃𝑒𝐸 ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣}))))))
2826, 27sylib 217 . . . 4 (𝑁𝑉 → ((𝑣 = 𝑁 ∨ (𝑣𝑉 ∧ ∃𝑒𝐸 (𝑁𝑒𝑣𝑒))) ↔ (𝑣 = 𝑁 ∨ (𝑣𝑉 ∧ ∃𝑒𝐸 ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣}))))))
29 elun 4145 . . . . 5 (𝑣 ∈ ({𝑁} ∪ {𝑛𝑉 ∣ ∃𝑒𝐸 (𝑁𝑒𝑛𝑒)}) ↔ (𝑣 ∈ {𝑁} ∨ 𝑣 ∈ {𝑛𝑉 ∣ ∃𝑒𝐸 (𝑁𝑒𝑛𝑒)}))
30 velsn 4639 . . . . . 6 (𝑣 ∈ {𝑁} ↔ 𝑣 = 𝑁)
31 eleq1 2814 . . . . . . . . 9 (𝑛 = 𝑣 → (𝑛𝑒𝑣𝑒))
3231anbi2d 628 . . . . . . . 8 (𝑛 = 𝑣 → ((𝑁𝑒𝑛𝑒) ↔ (𝑁𝑒𝑣𝑒)))
3332rexbidv 3169 . . . . . . 7 (𝑛 = 𝑣 → (∃𝑒𝐸 (𝑁𝑒𝑛𝑒) ↔ ∃𝑒𝐸 (𝑁𝑒𝑣𝑒)))
3433elrab 3680 . . . . . 6 (𝑣 ∈ {𝑛𝑉 ∣ ∃𝑒𝐸 (𝑁𝑒𝑛𝑒)} ↔ (𝑣𝑉 ∧ ∃𝑒𝐸 (𝑁𝑒𝑣𝑒)))
3530, 34orbi12i 912 . . . . 5 ((𝑣 ∈ {𝑁} ∨ 𝑣 ∈ {𝑛𝑉 ∣ ∃𝑒𝐸 (𝑁𝑒𝑛𝑒)}) ↔ (𝑣 = 𝑁 ∨ (𝑣𝑉 ∧ ∃𝑒𝐸 (𝑁𝑒𝑣𝑒))))
3629, 35bitri 274 . . . 4 (𝑣 ∈ ({𝑁} ∪ {𝑛𝑉 ∣ ∃𝑒𝐸 (𝑁𝑒𝑛𝑒)}) ↔ (𝑣 = 𝑁 ∨ (𝑣𝑉 ∧ ∃𝑒𝐸 (𝑁𝑒𝑣𝑒))))
37 elun 4145 . . . . 5 (𝑣 ∈ ({𝑁} ∪ {𝑛𝑉 ∣ ∃𝑒𝐸 ((𝑛𝑁𝑁𝑒𝑛𝑒) ∨ (𝑛 = 𝑁𝑒 = {𝑛}))}) ↔ (𝑣 ∈ {𝑁} ∨ 𝑣 ∈ {𝑛𝑉 ∣ ∃𝑒𝐸 ((𝑛𝑁𝑁𝑒𝑛𝑒) ∨ (𝑛 = 𝑁𝑒 = {𝑛}))}))
38 neeq1 2993 . . . . . . . . . 10 (𝑛 = 𝑣 → (𝑛𝑁𝑣𝑁))
3938, 313anbi13d 1435 . . . . . . . . 9 (𝑛 = 𝑣 → ((𝑛𝑁𝑁𝑒𝑛𝑒) ↔ (𝑣𝑁𝑁𝑒𝑣𝑒)))
40 eqeq1 2730 . . . . . . . . . 10 (𝑛 = 𝑣 → (𝑛 = 𝑁𝑣 = 𝑁))
41 sneq 4633 . . . . . . . . . . 11 (𝑛 = 𝑣 → {𝑛} = {𝑣})
4241eqeq2d 2737 . . . . . . . . . 10 (𝑛 = 𝑣 → (𝑒 = {𝑛} ↔ 𝑒 = {𝑣}))
4340, 42anbi12d 630 . . . . . . . . 9 (𝑛 = 𝑣 → ((𝑛 = 𝑁𝑒 = {𝑛}) ↔ (𝑣 = 𝑁𝑒 = {𝑣})))
4439, 43orbi12d 916 . . . . . . . 8 (𝑛 = 𝑣 → (((𝑛𝑁𝑁𝑒𝑛𝑒) ∨ (𝑛 = 𝑁𝑒 = {𝑛})) ↔ ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣}))))
4544rexbidv 3169 . . . . . . 7 (𝑛 = 𝑣 → (∃𝑒𝐸 ((𝑛𝑁𝑁𝑒𝑛𝑒) ∨ (𝑛 = 𝑁𝑒 = {𝑛})) ↔ ∃𝑒𝐸 ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣}))))
4645elrab 3680 . . . . . 6 (𝑣 ∈ {𝑛𝑉 ∣ ∃𝑒𝐸 ((𝑛𝑁𝑁𝑒𝑛𝑒) ∨ (𝑛 = 𝑁𝑒 = {𝑛}))} ↔ (𝑣𝑉 ∧ ∃𝑒𝐸 ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣}))))
4730, 46orbi12i 912 . . . . 5 ((𝑣 ∈ {𝑁} ∨ 𝑣 ∈ {𝑛𝑉 ∣ ∃𝑒𝐸 ((𝑛𝑁𝑁𝑒𝑛𝑒) ∨ (𝑛 = 𝑁𝑒 = {𝑛}))}) ↔ (𝑣 = 𝑁 ∨ (𝑣𝑉 ∧ ∃𝑒𝐸 ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣})))))
4837, 47bitri 274 . . . 4 (𝑣 ∈ ({𝑁} ∪ {𝑛𝑉 ∣ ∃𝑒𝐸 ((𝑛𝑁𝑁𝑒𝑛𝑒) ∨ (𝑛 = 𝑁𝑒 = {𝑛}))}) ↔ (𝑣 = 𝑁 ∨ (𝑣𝑉 ∧ ∃𝑒𝐸 ((𝑣𝑁𝑁𝑒𝑣𝑒) ∨ (𝑣 = 𝑁𝑒 = {𝑣})))))
4928, 36, 483bitr4g 313 . . 3 (𝑁𝑉 → (𝑣 ∈ ({𝑁} ∪ {𝑛𝑉 ∣ ∃𝑒𝐸 (𝑁𝑒𝑛𝑒)}) ↔ 𝑣 ∈ ({𝑁} ∪ {𝑛𝑉 ∣ ∃𝑒𝐸 ((𝑛𝑁𝑁𝑒𝑛𝑒) ∨ (𝑛 = 𝑁𝑒 = {𝑛}))})))
5049eqrdv 2724 . 2 (𝑁𝑉 → ({𝑁} ∪ {𝑛𝑉 ∣ ∃𝑒𝐸 (𝑁𝑒𝑛𝑒)}) = ({𝑁} ∪ {𝑛𝑉 ∣ ∃𝑒𝐸 ((𝑛𝑁𝑁𝑒𝑛𝑒) ∨ (𝑛 = 𝑁𝑒 = {𝑛}))}))
51 dfvopnbgr2.v . . 3 𝑉 = (Vtx‘𝐺)
52 dfvopnbgr2.e . . 3 𝐸 = (Edg‘𝐺)
5351, 52dfclnbgr2 47431 . 2 (𝑁𝑉 → (𝐺 ClNeighbVtx 𝑁) = ({𝑁} ∪ {𝑛𝑉 ∣ ∃𝑒𝐸 (𝑁𝑒𝑛𝑒)}))
54 dfvopnbgr2.u . . . 4 𝑈 = {𝑛𝑉 ∣ (𝑛 ∈ (𝐺 NeighbVtx 𝑁) ∨ ∃𝑒𝐸 (𝑁 = 𝑛𝑒 = {𝑁}))}
5551, 52, 54dfvopnbgr2 47456 . . 3 (𝑁𝑉𝑈 = {𝑛𝑉 ∣ ∃𝑒𝐸 ((𝑛𝑁𝑁𝑒𝑛𝑒) ∨ (𝑛 = 𝑁𝑒 = {𝑛}))})
5655uneq2d 4160 . 2 (𝑁𝑉 → ({𝑁} ∪ 𝑈) = ({𝑁} ∪ {𝑛𝑉 ∣ ∃𝑒𝐸 ((𝑛𝑁𝑁𝑒𝑛𝑒) ∨ (𝑛 = 𝑁𝑒 = {𝑛}))}))
5750, 53, 563eqtr4d 2776 1 (𝑁𝑉 → (𝐺 ClNeighbVtx 𝑁) = ({𝑁} ∪ 𝑈))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 205  wa 394  wo 845  w3a 1084   = wceq 1534  wcel 2099  wne 2930  wrex 3060  {crab 3419  cun 3944  {csn 4623  cfv 6546  (class class class)co 7416  Vtxcvtx 28929  Edgcedg 28980   NeighbVtx cnbgr 29265   ClNeighbVtx cclnbgr 47426
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 1906  ax-6 1964  ax-7 2004  ax-8 2101  ax-9 2109  ax-10 2130  ax-11 2147  ax-12 2167  ax-ext 2697  ax-sep 5296  ax-nul 5303  ax-pr 5425  ax-un 7738
This theorem depends on definitions:  df-bi 206  df-an 395  df-or 846  df-3an 1086  df-tru 1537  df-fal 1547  df-ex 1775  df-nf 1779  df-sb 2061  df-mo 2529  df-eu 2558  df-clab 2704  df-cleq 2718  df-clel 2803  df-nfc 2878  df-ne 2931  df-ral 3052  df-rex 3061  df-rab 3420  df-v 3464  df-sbc 3776  df-csb 3892  df-dif 3949  df-un 3951  df-in 3953  df-ss 3963  df-nul 4323  df-if 4524  df-sn 4624  df-pr 4626  df-op 4630  df-uni 4906  df-iun 4995  df-br 5146  df-opab 5208  df-mpt 5229  df-id 5572  df-xp 5680  df-rel 5681  df-cnv 5682  df-co 5683  df-dm 5684  df-rn 5685  df-res 5686  df-ima 5687  df-iota 6498  df-fun 6548  df-fv 6554  df-ov 7419  df-oprab 7420  df-mpo 7421  df-1st 7995  df-2nd 7996  df-nbgr 29266  df-clnbgr 47427
This theorem is referenced by: (None)
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