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Mirrors > Home > MPE Home > Th. List > nbgr1vtx | Structured version Visualization version GIF version |
Description: In a graph with one vertex, all neighborhoods are empty. (Contributed by AV, 15-Nov-2020.) |
Ref | Expression |
---|---|
nbgr1vtx | ⊢ ((♯‘(Vtx‘𝐺)) = 1 → (𝐺 NeighbVtx 𝐾) = ∅) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | fvex 6681 | . . . . . . 7 ⊢ (Vtx‘𝐺) ∈ V | |
2 | hash1snb 13865 | . . . . . . 7 ⊢ ((Vtx‘𝐺) ∈ V → ((♯‘(Vtx‘𝐺)) = 1 ↔ ∃𝑣(Vtx‘𝐺) = {𝑣})) | |
3 | 1, 2 | ax-mp 5 | . . . . . 6 ⊢ ((♯‘(Vtx‘𝐺)) = 1 ↔ ∃𝑣(Vtx‘𝐺) = {𝑣}) |
4 | ral0 4396 | . . . . . . . . 9 ⊢ ∀𝑛 ∈ ∅ ¬ ∃𝑒 ∈ (Edg‘𝐺){𝐾, 𝑛} ⊆ 𝑒 | |
5 | eleq2 2821 | . . . . . . . . . . . 12 ⊢ ((Vtx‘𝐺) = {𝑣} → (𝐾 ∈ (Vtx‘𝐺) ↔ 𝐾 ∈ {𝑣})) | |
6 | simpr 488 | . . . . . . . . . . . . . . . 16 ⊢ ((𝐾 = 𝑣 ∧ (Vtx‘𝐺) = {𝑣}) → (Vtx‘𝐺) = {𝑣}) | |
7 | sneq 4523 | . . . . . . . . . . . . . . . . 17 ⊢ (𝐾 = 𝑣 → {𝐾} = {𝑣}) | |
8 | 7 | adantr 484 | . . . . . . . . . . . . . . . 16 ⊢ ((𝐾 = 𝑣 ∧ (Vtx‘𝐺) = {𝑣}) → {𝐾} = {𝑣}) |
9 | 6, 8 | difeq12d 4012 | . . . . . . . . . . . . . . 15 ⊢ ((𝐾 = 𝑣 ∧ (Vtx‘𝐺) = {𝑣}) → ((Vtx‘𝐺) ∖ {𝐾}) = ({𝑣} ∖ {𝑣})) |
10 | difid 4257 | . . . . . . . . . . . . . . 15 ⊢ ({𝑣} ∖ {𝑣}) = ∅ | |
11 | 9, 10 | eqtrdi 2789 | . . . . . . . . . . . . . 14 ⊢ ((𝐾 = 𝑣 ∧ (Vtx‘𝐺) = {𝑣}) → ((Vtx‘𝐺) ∖ {𝐾}) = ∅) |
12 | 11 | ex 416 | . . . . . . . . . . . . 13 ⊢ (𝐾 = 𝑣 → ((Vtx‘𝐺) = {𝑣} → ((Vtx‘𝐺) ∖ {𝐾}) = ∅)) |
13 | elsni 4530 | . . . . . . . . . . . . 13 ⊢ (𝐾 ∈ {𝑣} → 𝐾 = 𝑣) | |
14 | 12, 13 | syl11 33 | . . . . . . . . . . . 12 ⊢ ((Vtx‘𝐺) = {𝑣} → (𝐾 ∈ {𝑣} → ((Vtx‘𝐺) ∖ {𝐾}) = ∅)) |
15 | 5, 14 | sylbid 243 | . . . . . . . . . . 11 ⊢ ((Vtx‘𝐺) = {𝑣} → (𝐾 ∈ (Vtx‘𝐺) → ((Vtx‘𝐺) ∖ {𝐾}) = ∅)) |
16 | 15 | imp 410 | . . . . . . . . . 10 ⊢ (((Vtx‘𝐺) = {𝑣} ∧ 𝐾 ∈ (Vtx‘𝐺)) → ((Vtx‘𝐺) ∖ {𝐾}) = ∅) |
17 | 16 | raleqdv 3315 | . . . . . . . . 9 ⊢ (((Vtx‘𝐺) = {𝑣} ∧ 𝐾 ∈ (Vtx‘𝐺)) → (∀𝑛 ∈ ((Vtx‘𝐺) ∖ {𝐾}) ¬ ∃𝑒 ∈ (Edg‘𝐺){𝐾, 𝑛} ⊆ 𝑒 ↔ ∀𝑛 ∈ ∅ ¬ ∃𝑒 ∈ (Edg‘𝐺){𝐾, 𝑛} ⊆ 𝑒)) |
18 | 4, 17 | mpbiri 261 | . . . . . . . 8 ⊢ (((Vtx‘𝐺) = {𝑣} ∧ 𝐾 ∈ (Vtx‘𝐺)) → ∀𝑛 ∈ ((Vtx‘𝐺) ∖ {𝐾}) ¬ ∃𝑒 ∈ (Edg‘𝐺){𝐾, 𝑛} ⊆ 𝑒) |
19 | 18 | ex 416 | . . . . . . 7 ⊢ ((Vtx‘𝐺) = {𝑣} → (𝐾 ∈ (Vtx‘𝐺) → ∀𝑛 ∈ ((Vtx‘𝐺) ∖ {𝐾}) ¬ ∃𝑒 ∈ (Edg‘𝐺){𝐾, 𝑛} ⊆ 𝑒)) |
20 | 19 | exlimiv 1936 | . . . . . 6 ⊢ (∃𝑣(Vtx‘𝐺) = {𝑣} → (𝐾 ∈ (Vtx‘𝐺) → ∀𝑛 ∈ ((Vtx‘𝐺) ∖ {𝐾}) ¬ ∃𝑒 ∈ (Edg‘𝐺){𝐾, 𝑛} ⊆ 𝑒)) |
21 | 3, 20 | sylbi 220 | . . . . 5 ⊢ ((♯‘(Vtx‘𝐺)) = 1 → (𝐾 ∈ (Vtx‘𝐺) → ∀𝑛 ∈ ((Vtx‘𝐺) ∖ {𝐾}) ¬ ∃𝑒 ∈ (Edg‘𝐺){𝐾, 𝑛} ⊆ 𝑒)) |
22 | 21 | impcom 411 | . . . 4 ⊢ ((𝐾 ∈ (Vtx‘𝐺) ∧ (♯‘(Vtx‘𝐺)) = 1) → ∀𝑛 ∈ ((Vtx‘𝐺) ∖ {𝐾}) ¬ ∃𝑒 ∈ (Edg‘𝐺){𝐾, 𝑛} ⊆ 𝑒) |
23 | 22 | nbgr0vtxlem 27289 | . . 3 ⊢ ((𝐾 ∈ (Vtx‘𝐺) ∧ (♯‘(Vtx‘𝐺)) = 1) → (𝐺 NeighbVtx 𝐾) = ∅) |
24 | 23 | ex 416 | . 2 ⊢ (𝐾 ∈ (Vtx‘𝐺) → ((♯‘(Vtx‘𝐺)) = 1 → (𝐺 NeighbVtx 𝐾) = ∅)) |
25 | df-nel 3039 | . . . 4 ⊢ (𝐾 ∉ (Vtx‘𝐺) ↔ ¬ 𝐾 ∈ (Vtx‘𝐺)) | |
26 | eqid 2738 | . . . . 5 ⊢ (Vtx‘𝐺) = (Vtx‘𝐺) | |
27 | 26 | nbgrnvtx0 27273 | . . . 4 ⊢ (𝐾 ∉ (Vtx‘𝐺) → (𝐺 NeighbVtx 𝐾) = ∅) |
28 | 25, 27 | sylbir 238 | . . 3 ⊢ (¬ 𝐾 ∈ (Vtx‘𝐺) → (𝐺 NeighbVtx 𝐾) = ∅) |
29 | 28 | a1d 25 | . 2 ⊢ (¬ 𝐾 ∈ (Vtx‘𝐺) → ((♯‘(Vtx‘𝐺)) = 1 → (𝐺 NeighbVtx 𝐾) = ∅)) |
30 | 24, 29 | pm2.61i 185 | 1 ⊢ ((♯‘(Vtx‘𝐺)) = 1 → (𝐺 NeighbVtx 𝐾) = ∅) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 209 ∧ wa 399 = wceq 1542 ∃wex 1786 ∈ wcel 2113 ∉ wnel 3038 ∀wral 3053 ∃wrex 3054 Vcvv 3397 ∖ cdif 3838 ⊆ wss 3841 ∅c0 4209 {csn 4513 {cpr 4515 ‘cfv 6333 (class class class)co 7164 1c1 10609 ♯chash 13775 Vtxcvtx 26933 Edgcedg 26984 NeighbVtx cnbgr 27266 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1802 ax-4 1816 ax-5 1916 ax-6 1974 ax-7 2019 ax-8 2115 ax-9 2123 ax-10 2144 ax-11 2161 ax-12 2178 ax-ext 2710 ax-sep 5164 ax-nul 5171 ax-pow 5229 ax-pr 5293 ax-un 7473 ax-cnex 10664 ax-resscn 10665 ax-1cn 10666 ax-icn 10667 ax-addcl 10668 ax-addrcl 10669 ax-mulcl 10670 ax-mulrcl 10671 ax-mulcom 10672 ax-addass 10673 ax-mulass 10674 ax-distr 10675 ax-i2m1 10676 ax-1ne0 10677 ax-1rid 10678 ax-rnegex 10679 ax-rrecex 10680 ax-cnre 10681 ax-pre-lttri 10682 ax-pre-lttrn 10683 ax-pre-ltadd 10684 ax-pre-mulgt0 10685 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 847 df-3or 1089 df-3an 1090 df-tru 1545 df-fal 1555 df-ex 1787 df-nf 1791 df-sb 2074 df-mo 2540 df-eu 2570 df-clab 2717 df-cleq 2730 df-clel 2811 df-nfc 2881 df-ne 2935 df-nel 3039 df-ral 3058 df-rex 3059 df-reu 3060 df-rab 3062 df-v 3399 df-sbc 3680 df-csb 3789 df-dif 3844 df-un 3846 df-in 3848 df-ss 3858 df-pss 3860 df-nul 4210 df-if 4412 df-pw 4487 df-sn 4514 df-pr 4516 df-tp 4518 df-op 4520 df-uni 4794 df-int 4834 df-iun 4880 df-br 5028 df-opab 5090 df-mpt 5108 df-tr 5134 df-id 5425 df-eprel 5430 df-po 5438 df-so 5439 df-fr 5478 df-we 5480 df-xp 5525 df-rel 5526 df-cnv 5527 df-co 5528 df-dm 5529 df-rn 5530 df-res 5531 df-ima 5532 df-pred 6123 df-ord 6169 df-on 6170 df-lim 6171 df-suc 6172 df-iota 6291 df-fun 6335 df-fn 6336 df-f 6337 df-f1 6338 df-fo 6339 df-f1o 6340 df-fv 6341 df-riota 7121 df-ov 7167 df-oprab 7168 df-mpo 7169 df-om 7594 df-1st 7707 df-2nd 7708 df-wrecs 7969 df-recs 8030 df-rdg 8068 df-1o 8124 df-oadd 8128 df-er 8313 df-en 8549 df-dom 8550 df-sdom 8551 df-fin 8552 df-dju 9396 df-card 9434 df-pnf 10748 df-mnf 10749 df-xr 10750 df-ltxr 10751 df-le 10752 df-sub 10943 df-neg 10944 df-nn 11710 df-n0 11970 df-z 12056 df-uz 12318 df-fz 12975 df-hash 13776 df-nbgr 27267 |
This theorem is referenced by: rusgr1vtx 27522 |
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