MPE Home Metamath Proof Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  MPE Home  >  Th. List  >  frgrncvvdeqlem3 Structured version   Visualization version   GIF version

Theorem frgrncvvdeqlem3 28801
Description: Lemma 3 for frgrncvvdeq 28809. The unique neighbor of a vertex (expressed by a restricted iota) is the intersection of the corresponding neighborhoods. (Contributed by Alexander van der Vekens, 18-Dec-2017.) (Revised by AV, 10-May-2021.) (Proof shortened by AV, 12-Feb-2022.)
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 (𝜑𝑋𝑉)
frgrncvvdeq.y (𝜑𝑌𝑉)
frgrncvvdeq.ne (𝜑𝑋𝑌)
frgrncvvdeq.xy (𝜑𝑌𝐷)
frgrncvvdeq.f (𝜑𝐺 ∈ FriendGraph )
frgrncvvdeq.a 𝐴 = (𝑥𝐷 ↦ (𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸))
Assertion
Ref Expression
frgrncvvdeqlem3 ((𝜑𝑥𝐷) → {(𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸)} = ((𝐺 NeighbVtx 𝑥) ∩ 𝑁))
Distinct variable groups:   𝑦,𝐸   𝑦,𝐺   𝑦,𝑉   𝑦,𝑌   𝑥,𝑦   𝑦,𝑁
Allowed substitution hints:   𝜑(𝑥,𝑦)   𝐴(𝑥,𝑦)   𝐷(𝑥,𝑦)   𝐸(𝑥)   𝐺(𝑥)   𝑁(𝑥)   𝑉(𝑥)   𝑋(𝑥,𝑦)   𝑌(𝑥)

Proof of Theorem frgrncvvdeqlem3
Dummy variable 𝑛 is distinct from all other variables.
StepHypRef Expression
1 frgrncvvdeq.ny . . 3 𝑁 = (𝐺 NeighbVtx 𝑌)
21ineq2i 4154 . 2 ((𝐺 NeighbVtx 𝑥) ∩ 𝑁) = ((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌))
3 frgrncvvdeq.f . . . . 5 (𝜑𝐺 ∈ FriendGraph )
43adantr 481 . . . 4 ((𝜑𝑥𝐷) → 𝐺 ∈ FriendGraph )
5 frgrncvvdeq.nx . . . . . . . 8 𝐷 = (𝐺 NeighbVtx 𝑋)
65eleq2i 2829 . . . . . . 7 (𝑥𝐷𝑥 ∈ (𝐺 NeighbVtx 𝑋))
7 frgrncvvdeq.v1 . . . . . . . . 9 𝑉 = (Vtx‘𝐺)
87nbgrisvtx 27844 . . . . . . . 8 (𝑥 ∈ (𝐺 NeighbVtx 𝑋) → 𝑥𝑉)
98a1i 11 . . . . . . 7 (𝜑 → (𝑥 ∈ (𝐺 NeighbVtx 𝑋) → 𝑥𝑉))
106, 9biimtrid 241 . . . . . 6 (𝜑 → (𝑥𝐷𝑥𝑉))
1110imp 407 . . . . 5 ((𝜑𝑥𝐷) → 𝑥𝑉)
12 frgrncvvdeq.y . . . . . 6 (𝜑𝑌𝑉)
1312adantr 481 . . . . 5 ((𝜑𝑥𝐷) → 𝑌𝑉)
14 frgrncvvdeq.xy . . . . . . 7 (𝜑𝑌𝐷)
15 elnelne2 3058 . . . . . . 7 ((𝑥𝐷𝑌𝐷) → 𝑥𝑌)
1614, 15sylan2 593 . . . . . 6 ((𝑥𝐷𝜑) → 𝑥𝑌)
1716ancoms 459 . . . . 5 ((𝜑𝑥𝐷) → 𝑥𝑌)
1811, 13, 173jca 1127 . . . 4 ((𝜑𝑥𝐷) → (𝑥𝑉𝑌𝑉𝑥𝑌))
19 frgrncvvdeq.e . . . . 5 𝐸 = (Edg‘𝐺)
207, 19frcond3 28769 . . . 4 (𝐺 ∈ FriendGraph → ((𝑥𝑉𝑌𝑉𝑥𝑌) → ∃𝑛𝑉 ((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {𝑛}))
214, 18, 20sylc 65 . . 3 ((𝜑𝑥𝐷) → ∃𝑛𝑉 ((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {𝑛})
22 vex 3445 . . . . . . . . . 10 𝑛 ∈ V
23 elinsn 4656 . . . . . . . . . 10 ((𝑛 ∈ V ∧ ((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {𝑛}) → (𝑛 ∈ (𝐺 NeighbVtx 𝑥) ∧ 𝑛 ∈ (𝐺 NeighbVtx 𝑌)))
2422, 23mpan 687 . . . . . . . . 9 (((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {𝑛} → (𝑛 ∈ (𝐺 NeighbVtx 𝑥) ∧ 𝑛 ∈ (𝐺 NeighbVtx 𝑌)))
25 frgrusgr 28761 . . . . . . . . . . . . . . 15 (𝐺 ∈ FriendGraph → 𝐺 ∈ USGraph)
2619nbusgreledg 27856 . . . . . . . . . . . . . . . . 17 (𝐺 ∈ USGraph → (𝑛 ∈ (𝐺 NeighbVtx 𝑥) ↔ {𝑛, 𝑥} ∈ 𝐸))
27 prcom 4678 . . . . . . . . . . . . . . . . . 18 {𝑛, 𝑥} = {𝑥, 𝑛}
2827eleq1i 2828 . . . . . . . . . . . . . . . . 17 ({𝑛, 𝑥} ∈ 𝐸 ↔ {𝑥, 𝑛} ∈ 𝐸)
2926, 28bitrdi 286 . . . . . . . . . . . . . . . 16 (𝐺 ∈ USGraph → (𝑛 ∈ (𝐺 NeighbVtx 𝑥) ↔ {𝑥, 𝑛} ∈ 𝐸))
3029biimpd 228 . . . . . . . . . . . . . . 15 (𝐺 ∈ USGraph → (𝑛 ∈ (𝐺 NeighbVtx 𝑥) → {𝑥, 𝑛} ∈ 𝐸))
313, 25, 303syl 18 . . . . . . . . . . . . . 14 (𝜑 → (𝑛 ∈ (𝐺 NeighbVtx 𝑥) → {𝑥, 𝑛} ∈ 𝐸))
3231adantr 481 . . . . . . . . . . . . 13 ((𝜑𝑥𝐷) → (𝑛 ∈ (𝐺 NeighbVtx 𝑥) → {𝑥, 𝑛} ∈ 𝐸))
3332com12 32 . . . . . . . . . . . 12 (𝑛 ∈ (𝐺 NeighbVtx 𝑥) → ((𝜑𝑥𝐷) → {𝑥, 𝑛} ∈ 𝐸))
3433adantr 481 . . . . . . . . . . 11 ((𝑛 ∈ (𝐺 NeighbVtx 𝑥) ∧ 𝑛 ∈ (𝐺 NeighbVtx 𝑌)) → ((𝜑𝑥𝐷) → {𝑥, 𝑛} ∈ 𝐸))
3534imp 407 . . . . . . . . . 10 (((𝑛 ∈ (𝐺 NeighbVtx 𝑥) ∧ 𝑛 ∈ (𝐺 NeighbVtx 𝑌)) ∧ (𝜑𝑥𝐷)) → {𝑥, 𝑛} ∈ 𝐸)
361eqcomi 2746 . . . . . . . . . . . . . 14 (𝐺 NeighbVtx 𝑌) = 𝑁
3736eleq2i 2829 . . . . . . . . . . . . 13 (𝑛 ∈ (𝐺 NeighbVtx 𝑌) ↔ 𝑛𝑁)
3837biimpi 215 . . . . . . . . . . . 12 (𝑛 ∈ (𝐺 NeighbVtx 𝑌) → 𝑛𝑁)
3938adantl 482 . . . . . . . . . . 11 ((𝑛 ∈ (𝐺 NeighbVtx 𝑥) ∧ 𝑛 ∈ (𝐺 NeighbVtx 𝑌)) → 𝑛𝑁)
40 frgrncvvdeq.x . . . . . . . . . . . 12 (𝜑𝑋𝑉)
41 frgrncvvdeq.ne . . . . . . . . . . . 12 (𝜑𝑋𝑌)
42 frgrncvvdeq.a . . . . . . . . . . . 12 𝐴 = (𝑥𝐷 ↦ (𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸))
437, 19, 5, 1, 40, 12, 41, 14, 3, 42frgrncvvdeqlem2 28800 . . . . . . . . . . 11 ((𝜑𝑥𝐷) → ∃!𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸)
44 preq2 4680 . . . . . . . . . . . . 13 (𝑦 = 𝑛 → {𝑥, 𝑦} = {𝑥, 𝑛})
4544eleq1d 2822 . . . . . . . . . . . 12 (𝑦 = 𝑛 → ({𝑥, 𝑦} ∈ 𝐸 ↔ {𝑥, 𝑛} ∈ 𝐸))
4645riota2 7300 . . . . . . . . . . 11 ((𝑛𝑁 ∧ ∃!𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸) → ({𝑥, 𝑛} ∈ 𝐸 ↔ (𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸) = 𝑛))
4739, 43, 46syl2an 596 . . . . . . . . . 10 (((𝑛 ∈ (𝐺 NeighbVtx 𝑥) ∧ 𝑛 ∈ (𝐺 NeighbVtx 𝑌)) ∧ (𝜑𝑥𝐷)) → ({𝑥, 𝑛} ∈ 𝐸 ↔ (𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸) = 𝑛))
4835, 47mpbid 231 . . . . . . . . 9 (((𝑛 ∈ (𝐺 NeighbVtx 𝑥) ∧ 𝑛 ∈ (𝐺 NeighbVtx 𝑌)) ∧ (𝜑𝑥𝐷)) → (𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸) = 𝑛)
4924, 48sylan 580 . . . . . . . 8 ((((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {𝑛} ∧ (𝜑𝑥𝐷)) → (𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸) = 𝑛)
5049eqcomd 2743 . . . . . . 7 ((((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {𝑛} ∧ (𝜑𝑥𝐷)) → 𝑛 = (𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸))
5150sneqd 4583 . . . . . 6 ((((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {𝑛} ∧ (𝜑𝑥𝐷)) → {𝑛} = {(𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸)})
52 eqeq1 2741 . . . . . . 7 (((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {𝑛} → (((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {(𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸)} ↔ {𝑛} = {(𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸)}))
5352adantr 481 . . . . . 6 ((((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {𝑛} ∧ (𝜑𝑥𝐷)) → (((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {(𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸)} ↔ {𝑛} = {(𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸)}))
5451, 53mpbird 256 . . . . 5 ((((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {𝑛} ∧ (𝜑𝑥𝐷)) → ((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {(𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸)})
5554ex 413 . . . 4 (((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {𝑛} → ((𝜑𝑥𝐷) → ((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {(𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸)}))
5655rexlimivw 3145 . . 3 (∃𝑛𝑉 ((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {𝑛} → ((𝜑𝑥𝐷) → ((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {(𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸)}))
5721, 56mpcom 38 . 2 ((𝜑𝑥𝐷) → ((𝐺 NeighbVtx 𝑥) ∩ (𝐺 NeighbVtx 𝑌)) = {(𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸)})
582, 57eqtr2id 2790 1 ((𝜑𝑥𝐷) → {(𝑦𝑁 {𝑥, 𝑦} ∈ 𝐸)} = ((𝐺 NeighbVtx 𝑥) ∩ 𝑁))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 205  wa 396  w3a 1086   = wceq 1540  wcel 2105  wne 2941  wnel 3047  wrex 3071  ∃!wreu 3348  Vcvv 3441  cin 3896  {csn 4571  {cpr 4573  cmpt 5170  cfv 6466  crio 7273  (class class class)co 7317  Vtxcvtx 27502  Edgcedg 27553  USGraphcusgr 27655   NeighbVtx cnbgr 27835   FriendGraph cfrgr 28758
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1796  ax-4 1810  ax-5 1912  ax-6 1970  ax-7 2010  ax-8 2107  ax-9 2115  ax-10 2136  ax-11 2153  ax-12 2170  ax-ext 2708  ax-sep 5238  ax-nul 5245  ax-pow 5303  ax-pr 5367  ax-un 7630  ax-cnex 11007  ax-resscn 11008  ax-1cn 11009  ax-icn 11010  ax-addcl 11011  ax-addrcl 11012  ax-mulcl 11013  ax-mulrcl 11014  ax-mulcom 11015  ax-addass 11016  ax-mulass 11017  ax-distr 11018  ax-i2m1 11019  ax-1ne0 11020  ax-1rid 11021  ax-rnegex 11022  ax-rrecex 11023  ax-cnre 11024  ax-pre-lttri 11025  ax-pre-lttrn 11026  ax-pre-ltadd 11027  ax-pre-mulgt0 11028
This theorem depends on definitions:  df-bi 206  df-an 397  df-or 845  df-3or 1087  df-3an 1088  df-tru 1543  df-fal 1553  df-ex 1781  df-nf 1785  df-sb 2067  df-mo 2539  df-eu 2568  df-clab 2715  df-cleq 2729  df-clel 2815  df-nfc 2887  df-ne 2942  df-nel 3048  df-ral 3063  df-rex 3072  df-reu 3351  df-rab 3405  df-v 3443  df-sbc 3727  df-csb 3843  df-dif 3900  df-un 3902  df-in 3904  df-ss 3914  df-pss 3916  df-nul 4268  df-if 4472  df-pw 4547  df-sn 4572  df-pr 4574  df-op 4578  df-uni 4851  df-int 4893  df-iun 4939  df-br 5088  df-opab 5150  df-mpt 5171  df-tr 5205  df-id 5507  df-eprel 5513  df-po 5521  df-so 5522  df-fr 5563  df-we 5565  df-xp 5614  df-rel 5615  df-cnv 5616  df-co 5617  df-dm 5618  df-rn 5619  df-res 5620  df-ima 5621  df-pred 6225  df-ord 6292  df-on 6293  df-lim 6294  df-suc 6295  df-iota 6418  df-fun 6468  df-fn 6469  df-f 6470  df-f1 6471  df-fo 6472  df-f1o 6473  df-fv 6474  df-riota 7274  df-ov 7320  df-oprab 7321  df-mpo 7322  df-om 7760  df-1st 7878  df-2nd 7879  df-frecs 8146  df-wrecs 8177  df-recs 8251  df-rdg 8290  df-1o 8346  df-2o 8347  df-oadd 8350  df-er 8548  df-en 8784  df-dom 8785  df-sdom 8786  df-fin 8787  df-dju 9737  df-card 9775  df-pnf 11091  df-mnf 11092  df-xr 11093  df-ltxr 11094  df-le 11095  df-sub 11287  df-neg 11288  df-nn 12054  df-2 12116  df-n0 12314  df-xnn0 12386  df-z 12400  df-uz 12663  df-fz 13320  df-hash 14125  df-edg 27554  df-upgr 27588  df-umgr 27589  df-usgr 27657  df-nbgr 27836  df-frgr 28759
This theorem is referenced by:  frgrncvvdeqlem5  28803
  Copyright terms: Public domain W3C validator