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Mirrors > Home > MPE Home > Th. List > frgrwopreglem5a | Structured version Visualization version GIF version |
Description: If a friendship graph has two vertices with the same degree and two other vertices with different degrees, then there is a 4-cycle in the graph. Alternate version of frgrwopreglem5 27746 without a fixed degree and without using the sets 𝐴 and 𝐵. (Contributed by Alexander van der Vekens, 31-Dec-2017.) (Revised by AV, 4-Feb-2022.) |
Ref | Expression |
---|---|
frgrncvvdeq.v | ⊢ 𝑉 = (Vtx‘𝐺) |
frgrncvvdeq.d | ⊢ 𝐷 = (VtxDeg‘𝐺) |
frgrwopreglem4a.e | ⊢ 𝐸 = (Edg‘𝐺) |
Ref | Expression |
---|---|
frgrwopreglem5a | ⊢ ((𝐺 ∈ FriendGraph ∧ ((𝐴 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉) ∧ (𝐵 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉)) ∧ ((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌))) → (({𝐴, 𝐵} ∈ 𝐸 ∧ {𝐵, 𝑋} ∈ 𝐸) ∧ ({𝑋, 𝑌} ∈ 𝐸 ∧ {𝑌, 𝐴} ∈ 𝐸))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | id 22 | . . 3 ⊢ (𝐺 ∈ FriendGraph → 𝐺 ∈ FriendGraph ) | |
2 | simpl 476 | . . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉) → 𝐴 ∈ 𝑉) | |
3 | simpl 476 | . . . 4 ⊢ ((𝐵 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉) → 𝐵 ∈ 𝑉) | |
4 | 2, 3 | anim12i 606 | . . 3 ⊢ (((𝐴 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉) ∧ (𝐵 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉)) → (𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑉)) |
5 | simp2 1128 | . . 3 ⊢ (((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌)) → (𝐷‘𝐴) ≠ (𝐷‘𝐵)) | |
6 | frgrncvvdeq.v | . . . 4 ⊢ 𝑉 = (Vtx‘𝐺) | |
7 | frgrncvvdeq.d | . . . 4 ⊢ 𝐷 = (VtxDeg‘𝐺) | |
8 | frgrwopreglem4a.e | . . . 4 ⊢ 𝐸 = (Edg‘𝐺) | |
9 | 6, 7, 8 | frgrwopreglem4a 27735 | . . 3 ⊢ ((𝐺 ∈ FriendGraph ∧ (𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑉) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵)) → {𝐴, 𝐵} ∈ 𝐸) |
10 | 1, 4, 5, 9 | syl3an 1160 | . 2 ⊢ ((𝐺 ∈ FriendGraph ∧ ((𝐴 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉) ∧ (𝐵 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉)) ∧ ((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌))) → {𝐴, 𝐵} ∈ 𝐸) |
11 | simpr 479 | . . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉) → 𝑋 ∈ 𝑉) | |
12 | 11, 3 | anim12ci 607 | . . 3 ⊢ (((𝐴 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉) ∧ (𝐵 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉)) → (𝐵 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉)) |
13 | pm13.18 3050 | . . . . 5 ⊢ (((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵)) → (𝐷‘𝑋) ≠ (𝐷‘𝐵)) | |
14 | 13 | 3adant3 1123 | . . . 4 ⊢ (((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌)) → (𝐷‘𝑋) ≠ (𝐷‘𝐵)) |
15 | 14 | necomd 3024 | . . 3 ⊢ (((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌)) → (𝐷‘𝐵) ≠ (𝐷‘𝑋)) |
16 | 6, 7, 8 | frgrwopreglem4a 27735 | . . 3 ⊢ ((𝐺 ∈ FriendGraph ∧ (𝐵 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉) ∧ (𝐷‘𝐵) ≠ (𝐷‘𝑋)) → {𝐵, 𝑋} ∈ 𝐸) |
17 | 1, 12, 15, 16 | syl3an 1160 | . 2 ⊢ ((𝐺 ∈ FriendGraph ∧ ((𝐴 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉) ∧ (𝐵 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉)) ∧ ((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌))) → {𝐵, 𝑋} ∈ 𝐸) |
18 | simpr 479 | . . . . 5 ⊢ ((𝐵 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉) → 𝑌 ∈ 𝑉) | |
19 | 11, 18 | anim12i 606 | . . . 4 ⊢ (((𝐴 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉) ∧ (𝐵 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉)) → (𝑋 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉)) |
20 | simp3 1129 | . . . 4 ⊢ (((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌)) → (𝐷‘𝑋) ≠ (𝐷‘𝑌)) | |
21 | 6, 7, 8 | frgrwopreglem4a 27735 | . . . 4 ⊢ ((𝐺 ∈ FriendGraph ∧ (𝑋 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌)) → {𝑋, 𝑌} ∈ 𝐸) |
22 | 1, 19, 20, 21 | syl3an 1160 | . . 3 ⊢ ((𝐺 ∈ FriendGraph ∧ ((𝐴 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉) ∧ (𝐵 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉)) ∧ ((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌))) → {𝑋, 𝑌} ∈ 𝐸) |
23 | 2, 18 | anim12ci 607 | . . . 4 ⊢ (((𝐴 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉) ∧ (𝐵 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉)) → (𝑌 ∈ 𝑉 ∧ 𝐴 ∈ 𝑉)) |
24 | pm13.181 3052 | . . . . . 6 ⊢ (((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌)) → (𝐷‘𝐴) ≠ (𝐷‘𝑌)) | |
25 | 24 | 3adant2 1122 | . . . . 5 ⊢ (((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌)) → (𝐷‘𝐴) ≠ (𝐷‘𝑌)) |
26 | 25 | necomd 3024 | . . . 4 ⊢ (((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌)) → (𝐷‘𝑌) ≠ (𝐷‘𝐴)) |
27 | 6, 7, 8 | frgrwopreglem4a 27735 | . . . 4 ⊢ ((𝐺 ∈ FriendGraph ∧ (𝑌 ∈ 𝑉 ∧ 𝐴 ∈ 𝑉) ∧ (𝐷‘𝑌) ≠ (𝐷‘𝐴)) → {𝑌, 𝐴} ∈ 𝐸) |
28 | 1, 23, 26, 27 | syl3an 1160 | . . 3 ⊢ ((𝐺 ∈ FriendGraph ∧ ((𝐴 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉) ∧ (𝐵 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉)) ∧ ((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌))) → {𝑌, 𝐴} ∈ 𝐸) |
29 | 22, 28 | jca 507 | . 2 ⊢ ((𝐺 ∈ FriendGraph ∧ ((𝐴 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉) ∧ (𝐵 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉)) ∧ ((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌))) → ({𝑋, 𝑌} ∈ 𝐸 ∧ {𝑌, 𝐴} ∈ 𝐸)) |
30 | 10, 17, 29 | jca31 510 | 1 ⊢ ((𝐺 ∈ FriendGraph ∧ ((𝐴 ∈ 𝑉 ∧ 𝑋 ∈ 𝑉) ∧ (𝐵 ∈ 𝑉 ∧ 𝑌 ∈ 𝑉)) ∧ ((𝐷‘𝐴) = (𝐷‘𝑋) ∧ (𝐷‘𝐴) ≠ (𝐷‘𝐵) ∧ (𝐷‘𝑋) ≠ (𝐷‘𝑌))) → (({𝐴, 𝐵} ∈ 𝐸 ∧ {𝐵, 𝑋} ∈ 𝐸) ∧ ({𝑋, 𝑌} ∈ 𝐸 ∧ {𝑌, 𝐴} ∈ 𝐸))) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 386 ∧ w3a 1071 = wceq 1601 ∈ wcel 2107 ≠ wne 2969 {cpr 4400 ‘cfv 6137 Vtxcvtx 26361 Edgcedg 26412 VtxDegcvtxdg 26830 FriendGraph cfrgr 27681 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1839 ax-4 1853 ax-5 1953 ax-6 2021 ax-7 2055 ax-8 2109 ax-9 2116 ax-10 2135 ax-11 2150 ax-12 2163 ax-13 2334 ax-ext 2754 ax-rep 5008 ax-sep 5019 ax-nul 5027 ax-pow 5079 ax-pr 5140 ax-un 7228 ax-cnex 10330 ax-resscn 10331 ax-1cn 10332 ax-icn 10333 ax-addcl 10334 ax-addrcl 10335 ax-mulcl 10336 ax-mulrcl 10337 ax-mulcom 10338 ax-addass 10339 ax-mulass 10340 ax-distr 10341 ax-i2m1 10342 ax-1ne0 10343 ax-1rid 10344 ax-rnegex 10345 ax-rrecex 10346 ax-cnre 10347 ax-pre-lttri 10348 ax-pre-lttrn 10349 ax-pre-ltadd 10350 ax-pre-mulgt0 10351 |
This theorem depends on definitions: df-bi 199 df-an 387 df-or 837 df-3or 1072 df-3an 1073 df-tru 1605 df-fal 1615 df-ex 1824 df-nf 1828 df-sb 2012 df-mo 2551 df-eu 2587 df-clab 2764 df-cleq 2770 df-clel 2774 df-nfc 2921 df-ne 2970 df-nel 3076 df-ral 3095 df-rex 3096 df-reu 3097 df-rmo 3098 df-rab 3099 df-v 3400 df-sbc 3653 df-csb 3752 df-dif 3795 df-un 3797 df-in 3799 df-ss 3806 df-pss 3808 df-nul 4142 df-if 4308 df-pw 4381 df-sn 4399 df-pr 4401 df-tp 4403 df-op 4405 df-uni 4674 df-int 4713 df-iun 4757 df-br 4889 df-opab 4951 df-mpt 4968 df-tr 4990 df-id 5263 df-eprel 5268 df-po 5276 df-so 5277 df-fr 5316 df-we 5318 df-xp 5363 df-rel 5364 df-cnv 5365 df-co 5366 df-dm 5367 df-rn 5368 df-res 5369 df-ima 5370 df-pred 5935 df-ord 5981 df-on 5982 df-lim 5983 df-suc 5984 df-iota 6101 df-fun 6139 df-fn 6140 df-f 6141 df-f1 6142 df-fo 6143 df-f1o 6144 df-fv 6145 df-riota 6885 df-ov 6927 df-oprab 6928 df-mpt2 6929 df-om 7346 df-1st 7447 df-2nd 7448 df-wrecs 7691 df-recs 7753 df-rdg 7791 df-1o 7845 df-2o 7846 df-oadd 7849 df-er 8028 df-en 8244 df-dom 8245 df-sdom 8246 df-fin 8247 df-card 9100 df-cda 9327 df-pnf 10415 df-mnf 10416 df-xr 10417 df-ltxr 10418 df-le 10419 df-sub 10610 df-neg 10611 df-nn 11380 df-2 11443 df-n0 11648 df-xnn0 11720 df-z 11734 df-uz 11998 df-xadd 12263 df-fz 12649 df-hash 13442 df-edg 26413 df-uhgr 26423 df-ushgr 26424 df-upgr 26447 df-umgr 26448 df-uspgr 26516 df-usgr 26517 df-nbgr 26697 df-vtxdg 26831 df-frgr 27682 |
This theorem is referenced by: frgrwopreglem5 27746 |
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