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Mirrors > Home > MPE Home > Th. List > nbfusgrlevtxm1 | Structured version Visualization version GIF version |
Description: The number of neighbors of a vertex is at most the number of vertices of the graph minus 1 in a finite simple graph. (Contributed by AV, 16-Dec-2020.) (Proof shortened by AV, 13-Feb-2022.) |
Ref | Expression |
---|---|
hashnbusgrnn0.v | ⊢ 𝑉 = (Vtx‘𝐺) |
Ref | Expression |
---|---|
nbfusgrlevtxm1 | ⊢ ((𝐺 ∈ FinUSGraph ∧ 𝑈 ∈ 𝑉) → (♯‘(𝐺 NeighbVtx 𝑈)) ≤ ((♯‘𝑉) − 1)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | hashnbusgrnn0.v | . . . . 5 ⊢ 𝑉 = (Vtx‘𝐺) | |
2 | 1 | fvexi 6785 | . . . 4 ⊢ 𝑉 ∈ V |
3 | 2 | difexi 5256 | . . 3 ⊢ (𝑉 ∖ {𝑈}) ∈ V |
4 | 1 | nbgrssovtx 27726 | . . . 4 ⊢ (𝐺 NeighbVtx 𝑈) ⊆ (𝑉 ∖ {𝑈}) |
5 | 4 | a1i 11 | . . 3 ⊢ ((𝐺 ∈ FinUSGraph ∧ 𝑈 ∈ 𝑉) → (𝐺 NeighbVtx 𝑈) ⊆ (𝑉 ∖ {𝑈})) |
6 | hashss 14122 | . . 3 ⊢ (((𝑉 ∖ {𝑈}) ∈ V ∧ (𝐺 NeighbVtx 𝑈) ⊆ (𝑉 ∖ {𝑈})) → (♯‘(𝐺 NeighbVtx 𝑈)) ≤ (♯‘(𝑉 ∖ {𝑈}))) | |
7 | 3, 5, 6 | sylancr 587 | . 2 ⊢ ((𝐺 ∈ FinUSGraph ∧ 𝑈 ∈ 𝑉) → (♯‘(𝐺 NeighbVtx 𝑈)) ≤ (♯‘(𝑉 ∖ {𝑈}))) |
8 | 1 | fusgrvtxfi 27684 | . . 3 ⊢ (𝐺 ∈ FinUSGraph → 𝑉 ∈ Fin) |
9 | hashdifsn 14127 | . . . 4 ⊢ ((𝑉 ∈ Fin ∧ 𝑈 ∈ 𝑉) → (♯‘(𝑉 ∖ {𝑈})) = ((♯‘𝑉) − 1)) | |
10 | 9 | eqcomd 2746 | . . 3 ⊢ ((𝑉 ∈ Fin ∧ 𝑈 ∈ 𝑉) → ((♯‘𝑉) − 1) = (♯‘(𝑉 ∖ {𝑈}))) |
11 | 8, 10 | sylan 580 | . 2 ⊢ ((𝐺 ∈ FinUSGraph ∧ 𝑈 ∈ 𝑉) → ((♯‘𝑉) − 1) = (♯‘(𝑉 ∖ {𝑈}))) |
12 | 7, 11 | breqtrrd 5107 | 1 ⊢ ((𝐺 ∈ FinUSGraph ∧ 𝑈 ∈ 𝑉) → (♯‘(𝐺 NeighbVtx 𝑈)) ≤ ((♯‘𝑉) − 1)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 396 = wceq 1542 ∈ wcel 2110 Vcvv 3431 ∖ cdif 3889 ⊆ wss 3892 {csn 4567 class class class wbr 5079 ‘cfv 6432 (class class class)co 7271 Fincfn 8716 1c1 10873 ≤ cle 11011 − cmin 11205 ♯chash 14042 Vtxcvtx 27364 FinUSGraphcfusgr 27681 NeighbVtx cnbgr 27697 |
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 1917 ax-6 1975 ax-7 2015 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2158 ax-12 2175 ax-ext 2711 ax-sep 5227 ax-nul 5234 ax-pow 5292 ax-pr 5356 ax-un 7582 ax-cnex 10928 ax-resscn 10929 ax-1cn 10930 ax-icn 10931 ax-addcl 10932 ax-addrcl 10933 ax-mulcl 10934 ax-mulrcl 10935 ax-mulcom 10936 ax-addass 10937 ax-mulass 10938 ax-distr 10939 ax-i2m1 10940 ax-1ne0 10941 ax-1rid 10942 ax-rnegex 10943 ax-rrecex 10944 ax-cnre 10945 ax-pre-lttri 10946 ax-pre-lttrn 10947 ax-pre-ltadd 10948 ax-pre-mulgt0 10949 |
This theorem depends on definitions: df-bi 206 df-an 397 df-or 845 df-3or 1087 df-3an 1088 df-tru 1545 df-fal 1555 df-ex 1787 df-nf 1791 df-sb 2072 df-mo 2542 df-eu 2571 df-clab 2718 df-cleq 2732 df-clel 2818 df-nfc 2891 df-ne 2946 df-nel 3052 df-ral 3071 df-rex 3072 df-reu 3073 df-rab 3075 df-v 3433 df-sbc 3721 df-csb 3838 df-dif 3895 df-un 3897 df-in 3899 df-ss 3909 df-pss 3911 df-nul 4263 df-if 4466 df-pw 4541 df-sn 4568 df-pr 4570 df-op 4574 df-uni 4846 df-int 4886 df-iun 4932 df-br 5080 df-opab 5142 df-mpt 5163 df-tr 5197 df-id 5490 df-eprel 5496 df-po 5504 df-so 5505 df-fr 5545 df-we 5547 df-xp 5596 df-rel 5597 df-cnv 5598 df-co 5599 df-dm 5600 df-rn 5601 df-res 5602 df-ima 5603 df-pred 6201 df-ord 6268 df-on 6269 df-lim 6270 df-suc 6271 df-iota 6390 df-fun 6434 df-fn 6435 df-f 6436 df-f1 6437 df-fo 6438 df-f1o 6439 df-fv 6440 df-riota 7228 df-ov 7274 df-oprab 7275 df-mpo 7276 df-om 7707 df-1st 7824 df-2nd 7825 df-frecs 8088 df-wrecs 8119 df-recs 8193 df-rdg 8232 df-1o 8288 df-oadd 8292 df-er 8481 df-en 8717 df-dom 8718 df-sdom 8719 df-fin 8720 df-dju 9660 df-card 9698 df-pnf 11012 df-mnf 11013 df-xr 11014 df-ltxr 11015 df-le 11016 df-sub 11207 df-neg 11208 df-nn 11974 df-n0 12234 df-xnn0 12306 df-z 12320 df-uz 12582 df-fz 13239 df-hash 14043 df-fusgr 27682 df-nbgr 27698 |
This theorem is referenced by: (None) |
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