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Mirrors > Home > MPE Home > Th. List > eulerpath | Structured version Visualization version GIF version |
Description: A pseudograph with an Eulerian path has either zero or two vertices of odd degree. (Contributed by Mario Carneiro, 7-Apr-2015.) (Revised by AV, 26-Feb-2021.) |
Ref | Expression |
---|---|
eulerpathpr.v | ⊢ 𝑉 = (Vtx‘𝐺) |
Ref | Expression |
---|---|
eulerpath | ⊢ ((𝐺 ∈ UPGraph ∧ (EulerPaths‘𝐺) ≠ ∅) → (♯‘{𝑥 ∈ 𝑉 ∣ ¬ 2 ∥ ((VtxDeg‘𝐺)‘𝑥)}) ∈ {0, 2}) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | releupth 30233 | . . . . . 6 ⊢ Rel (EulerPaths‘𝐺) | |
2 | reldm0 5952 | . . . . . 6 ⊢ (Rel (EulerPaths‘𝐺) → ((EulerPaths‘𝐺) = ∅ ↔ dom (EulerPaths‘𝐺) = ∅)) | |
3 | 1, 2 | ax-mp 5 | . . . . 5 ⊢ ((EulerPaths‘𝐺) = ∅ ↔ dom (EulerPaths‘𝐺) = ∅) |
4 | 3 | necon3bii 2999 | . . . 4 ⊢ ((EulerPaths‘𝐺) ≠ ∅ ↔ dom (EulerPaths‘𝐺) ≠ ∅) |
5 | n0 4376 | . . . 4 ⊢ (dom (EulerPaths‘𝐺) ≠ ∅ ↔ ∃𝑓 𝑓 ∈ dom (EulerPaths‘𝐺)) | |
6 | 4, 5 | bitri 275 | . . 3 ⊢ ((EulerPaths‘𝐺) ≠ ∅ ↔ ∃𝑓 𝑓 ∈ dom (EulerPaths‘𝐺)) |
7 | vex 3492 | . . . . . 6 ⊢ 𝑓 ∈ V | |
8 | 7 | eldm 5925 | . . . . 5 ⊢ (𝑓 ∈ dom (EulerPaths‘𝐺) ↔ ∃𝑝 𝑓(EulerPaths‘𝐺)𝑝) |
9 | eulerpathpr.v | . . . . . . . 8 ⊢ 𝑉 = (Vtx‘𝐺) | |
10 | 9 | eulerpathpr 30274 | . . . . . . 7 ⊢ ((𝐺 ∈ UPGraph ∧ 𝑓(EulerPaths‘𝐺)𝑝) → (♯‘{𝑥 ∈ 𝑉 ∣ ¬ 2 ∥ ((VtxDeg‘𝐺)‘𝑥)}) ∈ {0, 2}) |
11 | 10 | expcom 413 | . . . . . 6 ⊢ (𝑓(EulerPaths‘𝐺)𝑝 → (𝐺 ∈ UPGraph → (♯‘{𝑥 ∈ 𝑉 ∣ ¬ 2 ∥ ((VtxDeg‘𝐺)‘𝑥)}) ∈ {0, 2})) |
12 | 11 | exlimiv 1929 | . . . . 5 ⊢ (∃𝑝 𝑓(EulerPaths‘𝐺)𝑝 → (𝐺 ∈ UPGraph → (♯‘{𝑥 ∈ 𝑉 ∣ ¬ 2 ∥ ((VtxDeg‘𝐺)‘𝑥)}) ∈ {0, 2})) |
13 | 8, 12 | sylbi 217 | . . . 4 ⊢ (𝑓 ∈ dom (EulerPaths‘𝐺) → (𝐺 ∈ UPGraph → (♯‘{𝑥 ∈ 𝑉 ∣ ¬ 2 ∥ ((VtxDeg‘𝐺)‘𝑥)}) ∈ {0, 2})) |
14 | 13 | exlimiv 1929 | . . 3 ⊢ (∃𝑓 𝑓 ∈ dom (EulerPaths‘𝐺) → (𝐺 ∈ UPGraph → (♯‘{𝑥 ∈ 𝑉 ∣ ¬ 2 ∥ ((VtxDeg‘𝐺)‘𝑥)}) ∈ {0, 2})) |
15 | 6, 14 | sylbi 217 | . 2 ⊢ ((EulerPaths‘𝐺) ≠ ∅ → (𝐺 ∈ UPGraph → (♯‘{𝑥 ∈ 𝑉 ∣ ¬ 2 ∥ ((VtxDeg‘𝐺)‘𝑥)}) ∈ {0, 2})) |
16 | 15 | impcom 407 | 1 ⊢ ((𝐺 ∈ UPGraph ∧ (EulerPaths‘𝐺) ≠ ∅) → (♯‘{𝑥 ∈ 𝑉 ∣ ¬ 2 ∥ ((VtxDeg‘𝐺)‘𝑥)}) ∈ {0, 2}) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 206 ∧ wa 395 = wceq 1537 ∃wex 1777 ∈ wcel 2108 ≠ wne 2946 {crab 3443 ∅c0 4352 {cpr 4650 class class class wbr 5166 dom cdm 5700 Rel wrel 5705 ‘cfv 6575 0cc0 11186 2c2 12350 ♯chash 14381 ∥ cdvds 16304 Vtxcvtx 29033 UPGraphcupgr 29117 VtxDegcvtxdg 29503 EulerPathsceupth 30231 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1793 ax-4 1807 ax-5 1909 ax-6 1967 ax-7 2007 ax-8 2110 ax-9 2118 ax-10 2141 ax-11 2158 ax-12 2178 ax-ext 2711 ax-rep 5303 ax-sep 5317 ax-nul 5324 ax-pow 5383 ax-pr 5447 ax-un 7772 ax-cnex 11242 ax-resscn 11243 ax-1cn 11244 ax-icn 11245 ax-addcl 11246 ax-addrcl 11247 ax-mulcl 11248 ax-mulrcl 11249 ax-mulcom 11250 ax-addass 11251 ax-mulass 11252 ax-distr 11253 ax-i2m1 11254 ax-1ne0 11255 ax-1rid 11256 ax-rnegex 11257 ax-rrecex 11258 ax-cnre 11259 ax-pre-lttri 11260 ax-pre-lttrn 11261 ax-pre-ltadd 11262 ax-pre-mulgt0 11263 ax-pre-sup 11264 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 847 df-ifp 1064 df-3or 1088 df-3an 1089 df-tru 1540 df-fal 1550 df-ex 1778 df-nf 1782 df-sb 2065 df-mo 2543 df-eu 2572 df-clab 2718 df-cleq 2732 df-clel 2819 df-nfc 2895 df-ne 2947 df-nel 3053 df-ral 3068 df-rex 3077 df-rmo 3388 df-reu 3389 df-rab 3444 df-v 3490 df-sbc 3805 df-csb 3922 df-dif 3979 df-un 3981 df-in 3983 df-ss 3993 df-pss 3996 df-nul 4353 df-if 4549 df-pw 4624 df-sn 4649 df-pr 4651 df-op 4655 df-uni 4932 df-int 4971 df-iun 5017 df-br 5167 df-opab 5229 df-mpt 5250 df-tr 5284 df-id 5593 df-eprel 5599 df-po 5607 df-so 5608 df-fr 5652 df-we 5654 df-xp 5706 df-rel 5707 df-cnv 5708 df-co 5709 df-dm 5710 df-rn 5711 df-res 5712 df-ima 5713 df-pred 6334 df-ord 6400 df-on 6401 df-lim 6402 df-suc 6403 df-iota 6527 df-fun 6577 df-fn 6578 df-f 6579 df-f1 6580 df-fo 6581 df-f1o 6582 df-fv 6583 df-riota 7406 df-ov 7453 df-oprab 7454 df-mpo 7455 df-om 7906 df-1st 8032 df-2nd 8033 df-frecs 8324 df-wrecs 8355 df-recs 8429 df-rdg 8468 df-1o 8524 df-2o 8525 df-oadd 8528 df-er 8765 df-map 8888 df-pm 8889 df-en 9006 df-dom 9007 df-sdom 9008 df-fin 9009 df-sup 9513 df-inf 9514 df-dju 9972 df-card 10010 df-pnf 11328 df-mnf 11329 df-xr 11330 df-ltxr 11331 df-le 11332 df-sub 11524 df-neg 11525 df-div 11950 df-nn 12296 df-2 12358 df-3 12359 df-n0 12556 df-xnn0 12628 df-z 12642 df-uz 12906 df-rp 13060 df-xadd 13178 df-fz 13570 df-fzo 13714 df-seq 14055 df-exp 14115 df-hash 14382 df-word 14565 df-cj 15150 df-re 15151 df-im 15152 df-sqrt 15286 df-abs 15287 df-dvds 16305 df-vtx 29035 df-iedg 29036 df-edg 29085 df-uhgr 29095 df-ushgr 29096 df-upgr 29119 df-uspgr 29187 df-vtxdg 29504 df-wlks 29637 df-trls 29730 df-eupth 30232 |
This theorem is referenced by: konigsberg 30291 |
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