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Mirrors > Home > MPE Home > Th. List > uspgredg2vtxeu | Structured version Visualization version GIF version |
Description: For a vertex incident to an edge there is exactly one other vertex incident to the edge in a simple pseudograph. (Contributed by AV, 18-Oct-2020.) (Revised by AV, 6-Dec-2020.) |
Ref | Expression |
---|---|
uspgredg2vtxeu | ⊢ ((𝐺 ∈ USPGraph ∧ 𝐸 ∈ (Edg‘𝐺) ∧ 𝑌 ∈ 𝐸) → ∃!𝑦 ∈ (Vtx‘𝐺)𝐸 = {𝑌, 𝑦}) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | uspgrupgr 26964 | . . 3 ⊢ (𝐺 ∈ USPGraph → 𝐺 ∈ UPGraph) | |
2 | eqid 2824 | . . . 4 ⊢ (Vtx‘𝐺) = (Vtx‘𝐺) | |
3 | eqid 2824 | . . . 4 ⊢ (Edg‘𝐺) = (Edg‘𝐺) | |
4 | 2, 3 | upgredg2vtx 26929 | . . 3 ⊢ ((𝐺 ∈ UPGraph ∧ 𝐸 ∈ (Edg‘𝐺) ∧ 𝑌 ∈ 𝐸) → ∃𝑦 ∈ (Vtx‘𝐺)𝐸 = {𝑌, 𝑦}) |
5 | 1, 4 | syl3an1 1159 | . 2 ⊢ ((𝐺 ∈ USPGraph ∧ 𝐸 ∈ (Edg‘𝐺) ∧ 𝑌 ∈ 𝐸) → ∃𝑦 ∈ (Vtx‘𝐺)𝐸 = {𝑌, 𝑦}) |
6 | eqtr2 2845 | . . . . 5 ⊢ ((𝐸 = {𝑌, 𝑦} ∧ 𝐸 = {𝑌, 𝑥}) → {𝑌, 𝑦} = {𝑌, 𝑥}) | |
7 | vex 3500 | . . . . . 6 ⊢ 𝑦 ∈ V | |
8 | vex 3500 | . . . . . 6 ⊢ 𝑥 ∈ V | |
9 | 7, 8 | preqr2 4783 | . . . . 5 ⊢ ({𝑌, 𝑦} = {𝑌, 𝑥} → 𝑦 = 𝑥) |
10 | 6, 9 | syl 17 | . . . 4 ⊢ ((𝐸 = {𝑌, 𝑦} ∧ 𝐸 = {𝑌, 𝑥}) → 𝑦 = 𝑥) |
11 | 10 | a1i 11 | . . 3 ⊢ (((𝐺 ∈ USPGraph ∧ 𝐸 ∈ (Edg‘𝐺) ∧ 𝑌 ∈ 𝐸) ∧ (𝑦 ∈ (Vtx‘𝐺) ∧ 𝑥 ∈ (Vtx‘𝐺))) → ((𝐸 = {𝑌, 𝑦} ∧ 𝐸 = {𝑌, 𝑥}) → 𝑦 = 𝑥)) |
12 | 11 | ralrimivva 3194 | . 2 ⊢ ((𝐺 ∈ USPGraph ∧ 𝐸 ∈ (Edg‘𝐺) ∧ 𝑌 ∈ 𝐸) → ∀𝑦 ∈ (Vtx‘𝐺)∀𝑥 ∈ (Vtx‘𝐺)((𝐸 = {𝑌, 𝑦} ∧ 𝐸 = {𝑌, 𝑥}) → 𝑦 = 𝑥)) |
13 | preq2 4673 | . . . 4 ⊢ (𝑦 = 𝑥 → {𝑌, 𝑦} = {𝑌, 𝑥}) | |
14 | 13 | eqeq2d 2835 | . . 3 ⊢ (𝑦 = 𝑥 → (𝐸 = {𝑌, 𝑦} ↔ 𝐸 = {𝑌, 𝑥})) |
15 | 14 | reu4 3725 | . 2 ⊢ (∃!𝑦 ∈ (Vtx‘𝐺)𝐸 = {𝑌, 𝑦} ↔ (∃𝑦 ∈ (Vtx‘𝐺)𝐸 = {𝑌, 𝑦} ∧ ∀𝑦 ∈ (Vtx‘𝐺)∀𝑥 ∈ (Vtx‘𝐺)((𝐸 = {𝑌, 𝑦} ∧ 𝐸 = {𝑌, 𝑥}) → 𝑦 = 𝑥))) |
16 | 5, 12, 15 | sylanbrc 585 | 1 ⊢ ((𝐺 ∈ USPGraph ∧ 𝐸 ∈ (Edg‘𝐺) ∧ 𝑌 ∈ 𝐸) → ∃!𝑦 ∈ (Vtx‘𝐺)𝐸 = {𝑌, 𝑦}) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 398 ∧ w3a 1083 = wceq 1536 ∈ wcel 2113 ∀wral 3141 ∃wrex 3142 ∃!wreu 3143 {cpr 4572 ‘cfv 6358 Vtxcvtx 26784 Edgcedg 26835 UPGraphcupgr 26868 USPGraphcuspgr 26936 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1795 ax-4 1809 ax-5 1910 ax-6 1969 ax-7 2014 ax-8 2115 ax-9 2123 ax-10 2144 ax-11 2160 ax-12 2176 ax-ext 2796 ax-rep 5193 ax-sep 5206 ax-nul 5213 ax-pow 5269 ax-pr 5333 ax-un 7464 ax-cnex 10596 ax-resscn 10597 ax-1cn 10598 ax-icn 10599 ax-addcl 10600 ax-addrcl 10601 ax-mulcl 10602 ax-mulrcl 10603 ax-mulcom 10604 ax-addass 10605 ax-mulass 10606 ax-distr 10607 ax-i2m1 10608 ax-1ne0 10609 ax-1rid 10610 ax-rnegex 10611 ax-rrecex 10612 ax-cnre 10613 ax-pre-lttri 10614 ax-pre-lttrn 10615 ax-pre-ltadd 10616 ax-pre-mulgt0 10617 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3or 1084 df-3an 1085 df-tru 1539 df-ex 1780 df-nf 1784 df-sb 2069 df-mo 2621 df-eu 2653 df-clab 2803 df-cleq 2817 df-clel 2896 df-nfc 2966 df-ne 3020 df-nel 3127 df-ral 3146 df-rex 3147 df-reu 3148 df-rmo 3149 df-rab 3150 df-v 3499 df-sbc 3776 df-csb 3887 df-dif 3942 df-un 3944 df-in 3946 df-ss 3955 df-pss 3957 df-nul 4295 df-if 4471 df-pw 4544 df-sn 4571 df-pr 4573 df-tp 4575 df-op 4577 df-uni 4842 df-int 4880 df-iun 4924 df-br 5070 df-opab 5132 df-mpt 5150 df-tr 5176 df-id 5463 df-eprel 5468 df-po 5477 df-so 5478 df-fr 5517 df-we 5519 df-xp 5564 df-rel 5565 df-cnv 5566 df-co 5567 df-dm 5568 df-rn 5569 df-res 5570 df-ima 5571 df-pred 6151 df-ord 6197 df-on 6198 df-lim 6199 df-suc 6200 df-iota 6317 df-fun 6360 df-fn 6361 df-f 6362 df-f1 6363 df-fo 6364 df-f1o 6365 df-fv 6366 df-riota 7117 df-ov 7162 df-oprab 7163 df-mpo 7164 df-om 7584 df-1st 7692 df-2nd 7693 df-wrecs 7950 df-recs 8011 df-rdg 8049 df-1o 8105 df-2o 8106 df-oadd 8109 df-er 8292 df-en 8513 df-dom 8514 df-sdom 8515 df-fin 8516 df-dju 9333 df-card 9371 df-pnf 10680 df-mnf 10681 df-xr 10682 df-ltxr 10683 df-le 10684 df-sub 10875 df-neg 10876 df-nn 11642 df-2 11703 df-n0 11901 df-xnn0 11971 df-z 11985 df-uz 12247 df-fz 12896 df-hash 13694 df-edg 26836 df-upgr 26870 df-uspgr 26938 |
This theorem is referenced by: usgredg2vtxeu 27006 uspgredg2vlem 27008 uspgredg2v 27009 |
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