Step |
Hyp |
Ref |
Expression |
1 |
|
dfnbgr3.v |
|- V = ( Vtx ` G ) |
2 |
|
dfnbgr3.i |
|- I = ( iEdg ` G ) |
3 |
|
eqid |
|- ( Edg ` G ) = ( Edg ` G ) |
4 |
1 3
|
nbgrval |
|- ( N e. V -> ( G NeighbVtx N ) = { n e. ( V \ { N } ) | E. e e. ( Edg ` G ) { N , n } C_ e } ) |
5 |
4
|
adantr |
|- ( ( N e. V /\ Fun I ) -> ( G NeighbVtx N ) = { n e. ( V \ { N } ) | E. e e. ( Edg ` G ) { N , n } C_ e } ) |
6 |
|
edgval |
|- ( Edg ` G ) = ran ( iEdg ` G ) |
7 |
2
|
eqcomi |
|- ( iEdg ` G ) = I |
8 |
7
|
rneqi |
|- ran ( iEdg ` G ) = ran I |
9 |
6 8
|
eqtri |
|- ( Edg ` G ) = ran I |
10 |
9
|
rexeqi |
|- ( E. e e. ( Edg ` G ) { N , n } C_ e <-> E. e e. ran I { N , n } C_ e ) |
11 |
|
funfn |
|- ( Fun I <-> I Fn dom I ) |
12 |
11
|
biimpi |
|- ( Fun I -> I Fn dom I ) |
13 |
12
|
adantl |
|- ( ( N e. V /\ Fun I ) -> I Fn dom I ) |
14 |
|
sseq2 |
|- ( e = ( I ` i ) -> ( { N , n } C_ e <-> { N , n } C_ ( I ` i ) ) ) |
15 |
14
|
rexrn |
|- ( I Fn dom I -> ( E. e e. ran I { N , n } C_ e <-> E. i e. dom I { N , n } C_ ( I ` i ) ) ) |
16 |
13 15
|
syl |
|- ( ( N e. V /\ Fun I ) -> ( E. e e. ran I { N , n } C_ e <-> E. i e. dom I { N , n } C_ ( I ` i ) ) ) |
17 |
10 16
|
syl5bb |
|- ( ( N e. V /\ Fun I ) -> ( E. e e. ( Edg ` G ) { N , n } C_ e <-> E. i e. dom I { N , n } C_ ( I ` i ) ) ) |
18 |
17
|
rabbidv |
|- ( ( N e. V /\ Fun I ) -> { n e. ( V \ { N } ) | E. e e. ( Edg ` G ) { N , n } C_ e } = { n e. ( V \ { N } ) | E. i e. dom I { N , n } C_ ( I ` i ) } ) |
19 |
5 18
|
eqtrd |
|- ( ( N e. V /\ Fun I ) -> ( G NeighbVtx N ) = { n e. ( V \ { N } ) | E. i e. dom I { N , n } C_ ( I ` i ) } ) |