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Mirrors > Home > MPE Home > Th. List > nbusgrf1o1 | Structured version Visualization version GIF version |
Description: The set of neighbors of a vertex is isomorphic to the set of edges containing the vertex in a simple graph. (Contributed by Alexander van der Vekens, 19-Dec-2017.) (Revised by AV, 28-Oct-2020.) |
Ref | Expression |
---|---|
nbusgrf1o1.v | ⊢ 𝑉 = (Vtx‘𝐺) |
nbusgrf1o1.e | ⊢ 𝐸 = (Edg‘𝐺) |
nbusgrf1o1.n | ⊢ 𝑁 = (𝐺 NeighbVtx 𝑈) |
nbusgrf1o1.i | ⊢ 𝐼 = {𝑒 ∈ 𝐸 ∣ 𝑈 ∈ 𝑒} |
Ref | Expression |
---|---|
nbusgrf1o1 | ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → ∃𝑓 𝑓:𝑁–1-1-onto→𝐼) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nbusgrf1o1.n | . . . 4 ⊢ 𝑁 = (𝐺 NeighbVtx 𝑈) | |
2 | ovex 6954 | . . . 4 ⊢ (𝐺 NeighbVtx 𝑈) ∈ V | |
3 | 1, 2 | eqeltri 2855 | . . 3 ⊢ 𝑁 ∈ V |
4 | mptexg 6756 | . . 3 ⊢ (𝑁 ∈ V → (𝑛 ∈ 𝑁 ↦ {𝑈, 𝑛}) ∈ V) | |
5 | 3, 4 | mp1i 13 | . 2 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → (𝑛 ∈ 𝑁 ↦ {𝑈, 𝑛}) ∈ V) |
6 | nbusgrf1o1.v | . . 3 ⊢ 𝑉 = (Vtx‘𝐺) | |
7 | nbusgrf1o1.e | . . 3 ⊢ 𝐸 = (Edg‘𝐺) | |
8 | nbusgrf1o1.i | . . 3 ⊢ 𝐼 = {𝑒 ∈ 𝐸 ∣ 𝑈 ∈ 𝑒} | |
9 | eqid 2778 | . . 3 ⊢ (𝑛 ∈ 𝑁 ↦ {𝑈, 𝑛}) = (𝑛 ∈ 𝑁 ↦ {𝑈, 𝑛}) | |
10 | 6, 7, 1, 8, 9 | nbusgrf1o0 26717 | . 2 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → (𝑛 ∈ 𝑁 ↦ {𝑈, 𝑛}):𝑁–1-1-onto→𝐼) |
11 | f1oeq1 6380 | . . 3 ⊢ (𝑓 = (𝑛 ∈ 𝑁 ↦ {𝑈, 𝑛}) → (𝑓:𝑁–1-1-onto→𝐼 ↔ (𝑛 ∈ 𝑁 ↦ {𝑈, 𝑛}):𝑁–1-1-onto→𝐼)) | |
12 | 11 | spcegv 3496 | . 2 ⊢ ((𝑛 ∈ 𝑁 ↦ {𝑈, 𝑛}) ∈ V → ((𝑛 ∈ 𝑁 ↦ {𝑈, 𝑛}):𝑁–1-1-onto→𝐼 → ∃𝑓 𝑓:𝑁–1-1-onto→𝐼)) |
13 | 5, 10, 12 | sylc 65 | 1 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → ∃𝑓 𝑓:𝑁–1-1-onto→𝐼) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 386 = wceq 1601 ∃wex 1823 ∈ wcel 2107 {crab 3094 Vcvv 3398 {cpr 4400 ↦ cmpt 4965 –1-1-onto→wf1o 6134 ‘cfv 6135 (class class class)co 6922 Vtxcvtx 26344 Edgcedg 26395 USGraphcusgr 26498 NeighbVtx cnbgr 26679 |
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 5006 ax-sep 5017 ax-nul 5025 ax-pow 5077 ax-pr 5138 ax-un 7226 ax-cnex 10328 ax-resscn 10329 ax-1cn 10330 ax-icn 10331 ax-addcl 10332 ax-addrcl 10333 ax-mulcl 10334 ax-mulrcl 10335 ax-mulcom 10336 ax-addass 10337 ax-mulass 10338 ax-distr 10339 ax-i2m1 10340 ax-1ne0 10341 ax-1rid 10342 ax-rnegex 10343 ax-rrecex 10344 ax-cnre 10345 ax-pre-lttri 10346 ax-pre-lttrn 10347 ax-pre-ltadd 10348 ax-pre-mulgt0 10349 |
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 4672 df-int 4711 df-iun 4755 df-br 4887 df-opab 4949 df-mpt 4966 df-tr 4988 df-id 5261 df-eprel 5266 df-po 5274 df-so 5275 df-fr 5314 df-we 5316 df-xp 5361 df-rel 5362 df-cnv 5363 df-co 5364 df-dm 5365 df-rn 5366 df-res 5367 df-ima 5368 df-pred 5933 df-ord 5979 df-on 5980 df-lim 5981 df-suc 5982 df-iota 6099 df-fun 6137 df-fn 6138 df-f 6139 df-f1 6140 df-fo 6141 df-f1o 6142 df-fv 6143 df-riota 6883 df-ov 6925 df-oprab 6926 df-mpt2 6927 df-om 7344 df-1st 7445 df-2nd 7446 df-wrecs 7689 df-recs 7751 df-rdg 7789 df-1o 7843 df-2o 7844 df-oadd 7847 df-er 8026 df-en 8242 df-dom 8243 df-sdom 8244 df-fin 8245 df-card 9098 df-cda 9325 df-pnf 10413 df-mnf 10414 df-xr 10415 df-ltxr 10416 df-le 10417 df-sub 10608 df-neg 10609 df-nn 11375 df-2 11438 df-n0 11643 df-xnn0 11715 df-z 11729 df-uz 11993 df-fz 12644 df-hash 13436 df-edg 26396 df-upgr 26430 df-umgr 26431 df-uspgr 26499 df-usgr 26500 df-nbgr 26680 |
This theorem is referenced by: nbusgrf1o 26719 |
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