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Mirrors > Home > MPE Home > Th. List > vtxdusgr0edgnelALT | Structured version Visualization version GIF version |
Description: Alternate proof of vtxdusgr0edgnel 26626, not based on vtxduhgr0edgnel 26625. A vertex in a simple graph has degree 0 if there is no edge incident with this vertex. (Contributed by AV, 17-Dec-2020.) (Proof modification is discouraged.) (New usage is discouraged.) |
Ref | Expression |
---|---|
vtxdushgrfvedg.v | ⊢ 𝑉 = (Vtx‘𝐺) |
vtxdushgrfvedg.e | ⊢ 𝐸 = (Edg‘𝐺) |
vtxdushgrfvedg.d | ⊢ 𝐷 = (VtxDeg‘𝐺) |
Ref | Expression |
---|---|
vtxdusgr0edgnelALT | ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → ((𝐷‘𝑈) = 0 ↔ ¬ ∃𝑒 ∈ 𝐸 𝑈 ∈ 𝑒)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | vtxdushgrfvedg.v | . . . 4 ⊢ 𝑉 = (Vtx‘𝐺) | |
2 | vtxdushgrfvedg.e | . . . 4 ⊢ 𝐸 = (Edg‘𝐺) | |
3 | vtxdushgrfvedg.d | . . . 4 ⊢ 𝐷 = (VtxDeg‘𝐺) | |
4 | 1, 2, 3 | vtxdusgrfvedg 26622 | . . 3 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → (𝐷‘𝑈) = (♯‘{𝑒 ∈ 𝐸 ∣ 𝑈 ∈ 𝑒})) |
5 | 4 | eqeq1d 2773 | . 2 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → ((𝐷‘𝑈) = 0 ↔ (♯‘{𝑒 ∈ 𝐸 ∣ 𝑈 ∈ 𝑒}) = 0)) |
6 | fvex 6344 | . . . . 5 ⊢ (Edg‘𝐺) ∈ V | |
7 | 2, 6 | eqeltri 2846 | . . . 4 ⊢ 𝐸 ∈ V |
8 | 7 | rabex 4947 | . . 3 ⊢ {𝑒 ∈ 𝐸 ∣ 𝑈 ∈ 𝑒} ∈ V |
9 | hasheq0 13356 | . . 3 ⊢ ({𝑒 ∈ 𝐸 ∣ 𝑈 ∈ 𝑒} ∈ V → ((♯‘{𝑒 ∈ 𝐸 ∣ 𝑈 ∈ 𝑒}) = 0 ↔ {𝑒 ∈ 𝐸 ∣ 𝑈 ∈ 𝑒} = ∅)) | |
10 | 8, 9 | mp1i 13 | . 2 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → ((♯‘{𝑒 ∈ 𝐸 ∣ 𝑈 ∈ 𝑒}) = 0 ↔ {𝑒 ∈ 𝐸 ∣ 𝑈 ∈ 𝑒} = ∅)) |
11 | rabeq0 4104 | . . 3 ⊢ ({𝑒 ∈ 𝐸 ∣ 𝑈 ∈ 𝑒} = ∅ ↔ ∀𝑒 ∈ 𝐸 ¬ 𝑈 ∈ 𝑒) | |
12 | ralnex 3141 | . . . 4 ⊢ (∀𝑒 ∈ 𝐸 ¬ 𝑈 ∈ 𝑒 ↔ ¬ ∃𝑒 ∈ 𝐸 𝑈 ∈ 𝑒) | |
13 | 12 | a1i 11 | . . 3 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → (∀𝑒 ∈ 𝐸 ¬ 𝑈 ∈ 𝑒 ↔ ¬ ∃𝑒 ∈ 𝐸 𝑈 ∈ 𝑒)) |
14 | 11, 13 | syl5bb 272 | . 2 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → ({𝑒 ∈ 𝐸 ∣ 𝑈 ∈ 𝑒} = ∅ ↔ ¬ ∃𝑒 ∈ 𝐸 𝑈 ∈ 𝑒)) |
15 | 5, 10, 14 | 3bitrd 294 | 1 ⊢ ((𝐺 ∈ USGraph ∧ 𝑈 ∈ 𝑉) → ((𝐷‘𝑈) = 0 ↔ ¬ ∃𝑒 ∈ 𝐸 𝑈 ∈ 𝑒)) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 196 ∧ wa 382 = wceq 1631 ∈ wcel 2145 ∀wral 3061 ∃wrex 3062 {crab 3065 Vcvv 3351 ∅c0 4063 ‘cfv 6030 0cc0 10142 ♯chash 13321 Vtxcvtx 26095 Edgcedg 26160 USGraphcusgr 26266 VtxDegcvtxdg 26596 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1870 ax-4 1885 ax-5 1991 ax-6 2057 ax-7 2093 ax-8 2147 ax-9 2154 ax-10 2174 ax-11 2190 ax-12 2203 ax-13 2408 ax-ext 2751 ax-rep 4905 ax-sep 4916 ax-nul 4924 ax-pow 4975 ax-pr 5035 ax-un 7100 ax-cnex 10198 ax-resscn 10199 ax-1cn 10200 ax-icn 10201 ax-addcl 10202 ax-addrcl 10203 ax-mulcl 10204 ax-mulrcl 10205 ax-mulcom 10206 ax-addass 10207 ax-mulass 10208 ax-distr 10209 ax-i2m1 10210 ax-1ne0 10211 ax-1rid 10212 ax-rnegex 10213 ax-rrecex 10214 ax-cnre 10215 ax-pre-lttri 10216 ax-pre-lttrn 10217 ax-pre-ltadd 10218 ax-pre-mulgt0 10219 |
This theorem depends on definitions: df-bi 197 df-an 383 df-or 837 df-3or 1072 df-3an 1073 df-tru 1634 df-ex 1853 df-nf 1858 df-sb 2050 df-eu 2622 df-mo 2623 df-clab 2758 df-cleq 2764 df-clel 2767 df-nfc 2902 df-ne 2944 df-nel 3047 df-ral 3066 df-rex 3067 df-reu 3068 df-rab 3070 df-v 3353 df-sbc 3588 df-csb 3683 df-dif 3726 df-un 3728 df-in 3730 df-ss 3737 df-pss 3739 df-nul 4064 df-if 4227 df-pw 4300 df-sn 4318 df-pr 4320 df-tp 4322 df-op 4324 df-uni 4576 df-int 4613 df-iun 4657 df-br 4788 df-opab 4848 df-mpt 4865 df-tr 4888 df-id 5158 df-eprel 5163 df-po 5171 df-so 5172 df-fr 5209 df-we 5211 df-xp 5256 df-rel 5257 df-cnv 5258 df-co 5259 df-dm 5260 df-rn 5261 df-res 5262 df-ima 5263 df-pred 5822 df-ord 5868 df-on 5869 df-lim 5870 df-suc 5871 df-iota 5993 df-fun 6032 df-fn 6033 df-f 6034 df-f1 6035 df-fo 6036 df-f1o 6037 df-fv 6038 df-riota 6757 df-ov 6799 df-oprab 6800 df-mpt2 6801 df-om 7217 df-1st 7319 df-2nd 7320 df-wrecs 7563 df-recs 7625 df-rdg 7663 df-1o 7717 df-er 7900 df-en 8114 df-dom 8115 df-sdom 8116 df-fin 8117 df-card 8969 df-pnf 10282 df-mnf 10283 df-xr 10284 df-ltxr 10285 df-le 10286 df-sub 10474 df-neg 10475 df-nn 11227 df-2 11285 df-n0 11500 df-xnn0 11571 df-z 11585 df-uz 11894 df-xadd 12152 df-fz 12534 df-hash 13322 df-edg 26161 df-uhgr 26174 df-ushgr 26175 df-upgr 26198 df-umgr 26199 df-uspgr 26267 df-usgr 26268 df-vtxdg 26597 |
This theorem is referenced by: (None) |
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