Theorem nbgrisvtx 26255

Description: Every neighbor of a class/vertex is a vertex. (Contributed by Alexander van der Vekens, 12-Oct-2017.) (Revised by AV, 26-Oct-2020.)

Hypothesis

Ref	Expression
nbgrisvtx.v	|- V = (Vtx ` G )

Assertion

Ref	Expression
nbgrisvtx	|- ( ( G e. W /\ N e. ( G NeighbVtx K ) ) -> N e. V )

Proof of Theorem nbgrisvtx

Dummy variable e is distinct from all other variables.

Step	Hyp	Ref	Expression
1		nbgrisvtx.v	. . . 4 |- V = (Vtx ` G )
2		eqid 2622	. . . 4 |- (Edg ` G ) = (Edg ` G )
3	1, 2	nbgrel 26238	. . 3 |- ( G e. W -> ( N e. ( G NeighbVtx K ) <-> ( ( N e. V /\ K e. V ) /\ N =/= K /\ E. e e. (Edg ` G ) { K , N } C_ e ) ) )
4		simp1l 1085	. . 3 |- ( ( ( N e. V /\ K e. V ) /\ N =/= K /\ E. e e. (Edg ` G ) { K , N } C_ e ) -> N e. V )
5	3, 4	syl6bi 243	. 2 |- ( G e. W -> ( N e. ( G NeighbVtx K ) -> N e. V ) )
6	5	imp 445	1 |- ( ( G e. W /\ N e. ( G NeighbVtx K ) ) -> N e. V )

Syntax hints:   -> wi 4   /\ wa 384   /\ w3a 1037   = wceq 1483   e. wcel 1990   =/= wne 2794   E.wrex 2913   C_ wss 3574   {cpr 4179   ` cfv 5888  (class class class)co 6650  Vtxcvtx 25874  Edgcedg 25939   NeighbVtx cnbgr 26224

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-8 1992  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-sep 4781  ax-nul 4789  ax-pow 4843  ax-pr 4906  ax-un 6949

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3an 1039  df-tru 1486  df-fal 1489  df-ex 1705  df-nf 1710  df-sb 1881  df-eu 2474  df-mo 2475  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ne 2795  df-ral 2917  df-rex 2918  df-rab 2921  df-v 3202  df-sbc 3436  df-csb 3534  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-nul 3916  df-if 4087  df-sn 4178  df-pr 4180  df-op 4184  df-uni 4437  df-iun 4522  df-br 4654  df-opab 4713  df-mpt 4730  df-id 5024  df-xp 5120  df-rel 5121  df-cnv 5122  df-co 5123  df-dm 5124  df-rn 5125  df-res 5126  df-ima 5127  df-iota 5851  df-fun 5890  df-fv 5896  df-ov 6653  df-oprab 6654  df-mpt2 6655  df-1st 7168  df-2nd 7169  df-nbgr 26228

This theorem is referenced by:  nbgrssvtx  26256  nbgrnself2  26259  nbgrssovtx  26260  frgrnbnb  27157  frgrncvvdeqlem2  27164  frgrncvvdeqlem3  27165  frgrncvvdeqlem9  27171  numclwwlkovf2exlem2  27212  numclwwlkovf2ex  27219  numclwlk1lem2foa  27224  numclwlk1lem2fo  27228