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Mirrors > Home > MPE Home > Th. List > fusgr1th | Structured version Visualization version GIF version |
Description: The sum of the degrees of all vertices of a finite simple graph is twice the size of the graph. See equation (1) in section I.1 in [Bollobas] p. 4. Also known as the "First Theorem of Graph Theory" (see https://charlesreid1.com/wiki/First_Theorem_of_Graph_Theory). (Contributed by AV, 26-Dec-2021.) |
Ref | Expression |
---|---|
sumvtxdg2size.v | β’ π = (VtxβπΊ) |
sumvtxdg2size.i | β’ πΌ = (iEdgβπΊ) |
sumvtxdg2size.d | β’ π· = (VtxDegβπΊ) |
Ref | Expression |
---|---|
fusgr1th | β’ (πΊ β FinUSGraph β Ξ£π£ β π (π·βπ£) = (2 Β· (β―βπΌ))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | sumvtxdg2size.v | . . 3 β’ π = (VtxβπΊ) | |
2 | sumvtxdg2size.i | . . 3 β’ πΌ = (iEdgβπΊ) | |
3 | 1, 2 | fusgrfupgrfs 29012 | . 2 β’ (πΊ β FinUSGraph β (πΊ β UPGraph β§ π β Fin β§ πΌ β Fin)) |
4 | sumvtxdg2size.d | . . 3 β’ π· = (VtxDegβπΊ) | |
5 | 1, 2, 4 | finsumvtxdg2size 29231 | . 2 β’ ((πΊ β UPGraph β§ π β Fin β§ πΌ β Fin) β Ξ£π£ β π (π·βπ£) = (2 Β· (β―βπΌ))) |
6 | 3, 5 | syl 17 | 1 β’ (πΊ β FinUSGraph β Ξ£π£ β π (π·βπ£) = (2 Β· (β―βπΌ))) |
Colors of variables: wff setvar class |
Syntax hints: β wi 4 β§ w3a 1084 = wceq 1533 β wcel 2098 βcfv 6533 (class class class)co 7401 Fincfn 8934 Β· cmul 11110 2c2 12263 β―chash 14286 Ξ£csu 15628 Vtxcvtx 28680 iEdgciedg 28681 UPGraphcupgr 28764 FinUSGraphcfusgr 28997 VtxDegcvtxdg 29146 |
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 2163 ax-ext 2695 ax-rep 5275 ax-sep 5289 ax-nul 5296 ax-pow 5353 ax-pr 5417 ax-un 7718 ax-inf2 9631 ax-cnex 11161 ax-resscn 11162 ax-1cn 11163 ax-icn 11164 ax-addcl 11165 ax-addrcl 11166 ax-mulcl 11167 ax-mulrcl 11168 ax-mulcom 11169 ax-addass 11170 ax-mulass 11171 ax-distr 11172 ax-i2m1 11173 ax-1ne0 11174 ax-1rid 11175 ax-rnegex 11176 ax-rrecex 11177 ax-cnre 11178 ax-pre-lttri 11179 ax-pre-lttrn 11180 ax-pre-ltadd 11181 ax-pre-mulgt0 11182 ax-pre-sup 11183 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 845 df-3or 1085 df-3an 1086 df-tru 1536 df-fal 1546 df-ex 1774 df-nf 1778 df-sb 2060 df-mo 2526 df-eu 2555 df-clab 2702 df-cleq 2716 df-clel 2802 df-nfc 2877 df-ne 2933 df-nel 3039 df-ral 3054 df-rex 3063 df-rmo 3368 df-reu 3369 df-rab 3425 df-v 3468 df-sbc 3770 df-csb 3886 df-dif 3943 df-un 3945 df-in 3947 df-ss 3957 df-pss 3959 df-nul 4315 df-if 4521 df-pw 4596 df-sn 4621 df-pr 4623 df-op 4627 df-uni 4900 df-int 4941 df-iun 4989 df-disj 5104 df-br 5139 df-opab 5201 df-mpt 5222 df-tr 5256 df-id 5564 df-eprel 5570 df-po 5578 df-so 5579 df-fr 5621 df-se 5622 df-we 5623 df-xp 5672 df-rel 5673 df-cnv 5674 df-co 5675 df-dm 5676 df-rn 5677 df-res 5678 df-ima 5679 df-pred 6290 df-ord 6357 df-on 6358 df-lim 6359 df-suc 6360 df-iota 6485 df-fun 6535 df-fn 6536 df-f 6537 df-f1 6538 df-fo 6539 df-f1o 6540 df-fv 6541 df-isom 6542 df-riota 7357 df-ov 7404 df-oprab 7405 df-mpo 7406 df-om 7849 df-1st 7968 df-2nd 7969 df-frecs 8261 df-wrecs 8292 df-recs 8366 df-rdg 8405 df-1o 8461 df-2o 8462 df-oadd 8465 df-er 8698 df-en 8935 df-dom 8936 df-sdom 8937 df-fin 8938 df-sup 9432 df-oi 9500 df-dju 9891 df-card 9929 df-pnf 11246 df-mnf 11247 df-xr 11248 df-ltxr 11249 df-le 11250 df-sub 11442 df-neg 11443 df-div 11868 df-nn 12209 df-2 12271 df-3 12272 df-n0 12469 df-xnn0 12541 df-z 12555 df-uz 12819 df-rp 12971 df-xadd 13089 df-fz 13481 df-fzo 13624 df-seq 13963 df-exp 14024 df-hash 14287 df-cj 15042 df-re 15043 df-im 15044 df-sqrt 15178 df-abs 15179 df-clim 15428 df-sum 15629 df-vtx 28682 df-iedg 28683 df-edg 28732 df-uhgr 28742 df-upgr 28766 df-umgr 28767 df-uspgr 28834 df-usgr 28835 df-fusgr 28998 df-vtxdg 29147 |
This theorem is referenced by: (None) |
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