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Mirrors > Home > MPE Home > Th. List > usgrvd0nedg | Structured version Visualization version GIF version |
Description: If a vertex in a simple graph has degree 0, the vertex is not adjacent to another vertex via an edge. (Contributed by Alexander van der Vekens, 20-Dec-2017.) (Revised by AV, 16-Dec-2020.) (Proof shortened by AV, 23-Dec-2020.) |
Ref | Expression |
---|---|
vtxdusgradjvtx.v | ⊢ 𝑉 = (Vtx‘𝐺) |
vtxdusgradjvtx.e | ⊢ 𝐸 = (Edg‘𝐺) |
Ref | Expression |
---|---|
usgrvd0nedg | ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → (((VtxDeg‘𝐺)‘𝑈) = 0 → ¬ ∃𝑣 ∈ 𝑉 {𝑈, 𝑣} ∈ 𝐸)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | vtxdusgradjvtx.v | . . . 4 ⊢ 𝑉 = (Vtx‘𝐺) | |
2 | vtxdusgradjvtx.e | . . . 4 ⊢ 𝐸 = (Edg‘𝐺) | |
3 | 1, 2 | vtxdusgradjvtx 26484 | . . 3 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → ((VtxDeg‘𝐺)‘𝑈) = (#‘{𝑣 ∈ 𝑉 ∣ {𝑈, 𝑣} ∈ 𝐸})) |
4 | 3 | eqeq1d 2653 | . 2 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → (((VtxDeg‘𝐺)‘𝑈) = 0 ↔ (#‘{𝑣 ∈ 𝑉 ∣ {𝑈, 𝑣} ∈ 𝐸}) = 0)) |
5 | fvex 6239 | . . . . . 6 ⊢ (Vtx‘𝐺) ∈ V | |
6 | 1, 5 | eqeltri 2726 | . . . . 5 ⊢ 𝑉 ∈ V |
7 | 6 | rabex 4845 | . . . 4 ⊢ {𝑣 ∈ 𝑉 ∣ {𝑈, 𝑣} ∈ 𝐸} ∈ V |
8 | hasheq0 13192 | . . . 4 ⊢ ({𝑣 ∈ 𝑉 ∣ {𝑈, 𝑣} ∈ 𝐸} ∈ V → ((#‘{𝑣 ∈ 𝑉 ∣ {𝑈, 𝑣} ∈ 𝐸}) = 0 ↔ {𝑣 ∈ 𝑉 ∣ {𝑈, 𝑣} ∈ 𝐸} = ∅)) | |
9 | 7, 8 | ax-mp 5 | . . 3 ⊢ ((#‘{𝑣 ∈ 𝑉 ∣ {𝑈, 𝑣} ∈ 𝐸}) = 0 ↔ {𝑣 ∈ 𝑉 ∣ {𝑈, 𝑣} ∈ 𝐸} = ∅) |
10 | rabeq0 3990 | . . . 4 ⊢ ({𝑣 ∈ 𝑉 ∣ {𝑈, 𝑣} ∈ 𝐸} = ∅ ↔ ∀𝑣 ∈ 𝑉 ¬ {𝑈, 𝑣} ∈ 𝐸) | |
11 | ralnex 3021 | . . . . . 6 ⊢ (∀𝑣 ∈ 𝑉 ¬ {𝑈, 𝑣} ∈ 𝐸 ↔ ¬ ∃𝑣 ∈ 𝑉 {𝑈, 𝑣} ∈ 𝐸) | |
12 | 11 | biimpi 206 | . . . . 5 ⊢ (∀𝑣 ∈ 𝑉 ¬ {𝑈, 𝑣} ∈ 𝐸 → ¬ ∃𝑣 ∈ 𝑉 {𝑈, 𝑣} ∈ 𝐸) |
13 | 12 | a1i 11 | . . . 4 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → (∀𝑣 ∈ 𝑉 ¬ {𝑈, 𝑣} ∈ 𝐸 → ¬ ∃𝑣 ∈ 𝑉 {𝑈, 𝑣} ∈ 𝐸)) |
14 | 10, 13 | syl5bi 232 | . . 3 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → ({𝑣 ∈ 𝑉 ∣ {𝑈, 𝑣} ∈ 𝐸} = ∅ → ¬ ∃𝑣 ∈ 𝑉 {𝑈, 𝑣} ∈ 𝐸)) |
15 | 9, 14 | syl5bi 232 | . 2 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → ((#‘{𝑣 ∈ 𝑉 ∣ {𝑈, 𝑣} ∈ 𝐸}) = 0 → ¬ ∃𝑣 ∈ 𝑉 {𝑈, 𝑣} ∈ 𝐸)) |
16 | 4, 15 | sylbid 230 | 1 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → (((VtxDeg‘𝐺)‘𝑈) = 0 → ¬ ∃𝑣 ∈ 𝑉 {𝑈, 𝑣} ∈ 𝐸)) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 196 ∧ wa 383 = wceq 1523 ∈ wcel 2030 ∀wral 2941 ∃wrex 2942 {crab 2945 Vcvv 3231 ∅c0 3948 {cpr 4212 ‘cfv 5926 0cc0 9974 #chash 13157 Vtxcvtx 25919 Edgcedg 25984 USGraphcusgr 26089 VtxDegcvtxdg 26417 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1762 ax-4 1777 ax-5 1879 ax-6 1945 ax-7 1981 ax-8 2032 ax-9 2039 ax-10 2059 ax-11 2074 ax-12 2087 ax-13 2282 ax-ext 2631 ax-rep 4804 ax-sep 4814 ax-nul 4822 ax-pow 4873 ax-pr 4936 ax-un 6991 ax-cnex 10030 ax-resscn 10031 ax-1cn 10032 ax-icn 10033 ax-addcl 10034 ax-addrcl 10035 ax-mulcl 10036 ax-mulrcl 10037 ax-mulcom 10038 ax-addass 10039 ax-mulass 10040 ax-distr 10041 ax-i2m1 10042 ax-1ne0 10043 ax-1rid 10044 ax-rnegex 10045 ax-rrecex 10046 ax-cnre 10047 ax-pre-lttri 10048 ax-pre-lttrn 10049 ax-pre-ltadd 10050 ax-pre-mulgt0 10051 |
This theorem depends on definitions: df-bi 197 df-or 384 df-an 385 df-3or 1055 df-3an 1056 df-tru 1526 df-fal 1529 df-ex 1745 df-nf 1750 df-sb 1938 df-eu 2502 df-mo 2503 df-clab 2638 df-cleq 2644 df-clel 2647 df-nfc 2782 df-ne 2824 df-nel 2927 df-ral 2946 df-rex 2947 df-reu 2948 df-rmo 2949 df-rab 2950 df-v 3233 df-sbc 3469 df-csb 3567 df-dif 3610 df-un 3612 df-in 3614 df-ss 3621 df-pss 3623 df-nul 3949 df-if 4120 df-pw 4193 df-sn 4211 df-pr 4213 df-tp 4215 df-op 4217 df-uni 4469 df-int 4508 df-iun 4554 df-br 4686 df-opab 4746 df-mpt 4763 df-tr 4786 df-id 5053 df-eprel 5058 df-po 5064 df-so 5065 df-fr 5102 df-we 5104 df-xp 5149 df-rel 5150 df-cnv 5151 df-co 5152 df-dm 5153 df-rn 5154 df-res 5155 df-ima 5156 df-pred 5718 df-ord 5764 df-on 5765 df-lim 5766 df-suc 5767 df-iota 5889 df-fun 5928 df-fn 5929 df-f 5930 df-f1 5931 df-fo 5932 df-f1o 5933 df-fv 5934 df-riota 6651 df-ov 6693 df-oprab 6694 df-mpt2 6695 df-om 7108 df-1st 7210 df-2nd 7211 df-wrecs 7452 df-recs 7513 df-rdg 7551 df-1o 7605 df-2o 7606 df-oadd 7609 df-er 7787 df-en 7998 df-dom 7999 df-sdom 8000 df-fin 8001 df-card 8803 df-cda 9028 df-pnf 10114 df-mnf 10115 df-xr 10116 df-ltxr 10117 df-le 10118 df-sub 10306 df-neg 10307 df-nn 11059 df-2 11117 df-n0 11331 df-xnn0 11402 df-z 11416 df-uz 11726 df-xadd 11985 df-fz 12365 df-hash 13158 df-edg 25985 df-uhgr 25998 df-ushgr 25999 df-upgr 26022 df-umgr 26023 df-uspgr 26090 df-usgr 26091 df-nbgr 26270 df-vtxdg 26418 |
This theorem is referenced by: (None) |
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