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Mirrors > Home > MPE Home > Th. List > uvtxnm1nbgr | Structured version Visualization version GIF version |
Description: A universal vertex has 𝑛 − 1 neighbors in a finite graph with 𝑛 vertices. (Contributed by Alexander van der Vekens, 14-Oct-2017.) (Revised by AV, 3-Nov-2020.) |
Ref | Expression |
---|---|
uvtxnm1nbgr.v | ⊢ 𝑉 = (Vtx‘𝐺) |
Ref | Expression |
---|---|
uvtxnm1nbgr | ⊢ ((𝐺 ∈ FinUSGraph ∧ 𝑁 ∈ (UnivVtx‘𝐺)) → (♯‘(𝐺 NeighbVtx 𝑁)) = ((♯‘𝑉) − 1)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | uvtxnm1nbgr.v | . . . . 5 ⊢ 𝑉 = (Vtx‘𝐺) | |
2 | 1 | uvtxnbgr 29328 | . . . 4 ⊢ (𝑁 ∈ (UnivVtx‘𝐺) → (𝐺 NeighbVtx 𝑁) = (𝑉 ∖ {𝑁})) |
3 | 2 | adantl 480 | . . 3 ⊢ ((𝐺 ∈ FinUSGraph ∧ 𝑁 ∈ (UnivVtx‘𝐺)) → (𝐺 NeighbVtx 𝑁) = (𝑉 ∖ {𝑁})) |
4 | 3 | fveq2d 6904 | . 2 ⊢ ((𝐺 ∈ FinUSGraph ∧ 𝑁 ∈ (UnivVtx‘𝐺)) → (♯‘(𝐺 NeighbVtx 𝑁)) = (♯‘(𝑉 ∖ {𝑁}))) |
5 | 1 | fusgrvtxfi 29247 | . . 3 ⊢ (𝐺 ∈ FinUSGraph → 𝑉 ∈ Fin) |
6 | 1 | uvtxisvtx 29317 | . . . 4 ⊢ (𝑁 ∈ (UnivVtx‘𝐺) → 𝑁 ∈ 𝑉) |
7 | 6 | snssd 4817 | . . 3 ⊢ (𝑁 ∈ (UnivVtx‘𝐺) → {𝑁} ⊆ 𝑉) |
8 | hashssdif 14424 | . . 3 ⊢ ((𝑉 ∈ Fin ∧ {𝑁} ⊆ 𝑉) → (♯‘(𝑉 ∖ {𝑁})) = ((♯‘𝑉) − (♯‘{𝑁}))) | |
9 | 5, 7, 8 | syl2an 594 | . 2 ⊢ ((𝐺 ∈ FinUSGraph ∧ 𝑁 ∈ (UnivVtx‘𝐺)) → (♯‘(𝑉 ∖ {𝑁})) = ((♯‘𝑉) − (♯‘{𝑁}))) |
10 | hashsng 14381 | . . . 4 ⊢ (𝑁 ∈ (UnivVtx‘𝐺) → (♯‘{𝑁}) = 1) | |
11 | 10 | adantl 480 | . . 3 ⊢ ((𝐺 ∈ FinUSGraph ∧ 𝑁 ∈ (UnivVtx‘𝐺)) → (♯‘{𝑁}) = 1) |
12 | 11 | oveq2d 7439 | . 2 ⊢ ((𝐺 ∈ FinUSGraph ∧ 𝑁 ∈ (UnivVtx‘𝐺)) → ((♯‘𝑉) − (♯‘{𝑁})) = ((♯‘𝑉) − 1)) |
13 | 4, 9, 12 | 3eqtrd 2769 | 1 ⊢ ((𝐺 ∈ FinUSGraph ∧ 𝑁 ∈ (UnivVtx‘𝐺)) → (♯‘(𝐺 NeighbVtx 𝑁)) = ((♯‘𝑉) − 1)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 394 = wceq 1533 ∈ wcel 2098 ∖ cdif 3943 ⊆ wss 3946 {csn 4632 ‘cfv 6553 (class class class)co 7423 Fincfn 8973 1c1 11155 − cmin 11490 ♯chash 14342 Vtxcvtx 28924 FinUSGraphcfusgr 29244 NeighbVtx cnbgr 29260 UnivVtxcuvtx 29313 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1789 ax-4 1803 ax-5 1905 ax-6 1963 ax-7 2003 ax-8 2100 ax-9 2108 ax-10 2129 ax-11 2146 ax-12 2166 ax-ext 2696 ax-sep 5303 ax-nul 5310 ax-pow 5368 ax-pr 5432 ax-un 7745 ax-cnex 11210 ax-resscn 11211 ax-1cn 11212 ax-icn 11213 ax-addcl 11214 ax-addrcl 11215 ax-mulcl 11216 ax-mulrcl 11217 ax-mulcom 11218 ax-addass 11219 ax-mulass 11220 ax-distr 11221 ax-i2m1 11222 ax-1ne0 11223 ax-1rid 11224 ax-rnegex 11225 ax-rrecex 11226 ax-cnre 11227 ax-pre-lttri 11228 ax-pre-lttrn 11229 ax-pre-ltadd 11230 ax-pre-mulgt0 11231 |
This theorem depends on definitions: df-bi 206 df-an 395 df-or 846 df-3or 1085 df-3an 1086 df-tru 1536 df-fal 1546 df-ex 1774 df-nf 1778 df-sb 2060 df-mo 2528 df-eu 2557 df-clab 2703 df-cleq 2717 df-clel 2802 df-nfc 2877 df-ne 2930 df-nel 3036 df-ral 3051 df-rex 3060 df-reu 3364 df-rab 3419 df-v 3463 df-sbc 3776 df-csb 3892 df-dif 3949 df-un 3951 df-in 3953 df-ss 3963 df-pss 3966 df-nul 4325 df-if 4533 df-pw 4608 df-sn 4633 df-pr 4635 df-op 4639 df-uni 4913 df-int 4954 df-iun 5002 df-br 5153 df-opab 5215 df-mpt 5236 df-tr 5270 df-id 5579 df-eprel 5585 df-po 5593 df-so 5594 df-fr 5636 df-we 5638 df-xp 5687 df-rel 5688 df-cnv 5689 df-co 5690 df-dm 5691 df-rn 5692 df-res 5693 df-ima 5694 df-pred 6311 df-ord 6378 df-on 6379 df-lim 6380 df-suc 6381 df-iota 6505 df-fun 6555 df-fn 6556 df-f 6557 df-f1 6558 df-fo 6559 df-f1o 6560 df-fv 6561 df-riota 7379 df-ov 7426 df-oprab 7427 df-mpo 7428 df-om 7876 df-1st 8002 df-2nd 8003 df-frecs 8295 df-wrecs 8326 df-recs 8400 df-rdg 8439 df-1o 8495 df-oadd 8499 df-er 8733 df-en 8974 df-dom 8975 df-sdom 8976 df-fin 8977 df-dju 9940 df-card 9978 df-pnf 11296 df-mnf 11297 df-xr 11298 df-ltxr 11299 df-le 11300 df-sub 11492 df-neg 11493 df-nn 12260 df-n0 12520 df-z 12606 df-uz 12870 df-fz 13534 df-hash 14343 df-fusgr 29245 df-nbgr 29261 df-uvtx 29314 |
This theorem is referenced by: uvtxnbvtxm1 29334 |
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