Step |
Hyp |
Ref |
Expression |
1 |
|
hashnbusgrnn0.v |
|- V = ( Vtx ` G ) |
2 |
|
ax-1 |
|- ( M e. ( G NeighbVtx U ) -> ( ( M e. V /\ M =/= U ) -> M e. ( G NeighbVtx U ) ) ) |
3 |
2
|
2a1d |
|- ( M e. ( G NeighbVtx U ) -> ( ( G e. FinUSGraph /\ U e. V ) -> ( ( # ` ( G NeighbVtx U ) ) = ( ( # ` V ) - 1 ) -> ( ( M e. V /\ M =/= U ) -> M e. ( G NeighbVtx U ) ) ) ) ) |
4 |
|
simpr |
|- ( ( -. M e. ( G NeighbVtx U ) /\ ( G e. FinUSGraph /\ U e. V ) ) -> ( G e. FinUSGraph /\ U e. V ) ) |
5 |
4
|
adantr |
|- ( ( ( -. M e. ( G NeighbVtx U ) /\ ( G e. FinUSGraph /\ U e. V ) ) /\ ( M e. V /\ M =/= U ) ) -> ( G e. FinUSGraph /\ U e. V ) ) |
6 |
|
simprl |
|- ( ( ( -. M e. ( G NeighbVtx U ) /\ ( G e. FinUSGraph /\ U e. V ) ) /\ ( M e. V /\ M =/= U ) ) -> M e. V ) |
7 |
|
simpr |
|- ( ( M e. V /\ M =/= U ) -> M =/= U ) |
8 |
7
|
adantl |
|- ( ( ( -. M e. ( G NeighbVtx U ) /\ ( G e. FinUSGraph /\ U e. V ) ) /\ ( M e. V /\ M =/= U ) ) -> M =/= U ) |
9 |
|
df-nel |
|- ( M e/ ( G NeighbVtx U ) <-> -. M e. ( G NeighbVtx U ) ) |
10 |
9
|
biimpri |
|- ( -. M e. ( G NeighbVtx U ) -> M e/ ( G NeighbVtx U ) ) |
11 |
10
|
adantr |
|- ( ( -. M e. ( G NeighbVtx U ) /\ ( G e. FinUSGraph /\ U e. V ) ) -> M e/ ( G NeighbVtx U ) ) |
12 |
11
|
adantr |
|- ( ( ( -. M e. ( G NeighbVtx U ) /\ ( G e. FinUSGraph /\ U e. V ) ) /\ ( M e. V /\ M =/= U ) ) -> M e/ ( G NeighbVtx U ) ) |
13 |
1
|
nbfusgrlevtxm2 |
|- ( ( ( G e. FinUSGraph /\ U e. V ) /\ ( M e. V /\ M =/= U /\ M e/ ( G NeighbVtx U ) ) ) -> ( # ` ( G NeighbVtx U ) ) <_ ( ( # ` V ) - 2 ) ) |
14 |
5 6 8 12 13
|
syl13anc |
|- ( ( ( -. M e. ( G NeighbVtx U ) /\ ( G e. FinUSGraph /\ U e. V ) ) /\ ( M e. V /\ M =/= U ) ) -> ( # ` ( G NeighbVtx U ) ) <_ ( ( # ` V ) - 2 ) ) |
15 |
|
breq1 |
|- ( ( # ` ( G NeighbVtx U ) ) = ( ( # ` V ) - 1 ) -> ( ( # ` ( G NeighbVtx U ) ) <_ ( ( # ` V ) - 2 ) <-> ( ( # ` V ) - 1 ) <_ ( ( # ` V ) - 2 ) ) ) |
16 |
15
|
adantl |
|- ( ( ( ( -. M e. ( G NeighbVtx U ) /\ ( G e. FinUSGraph /\ U e. V ) ) /\ ( M e. V /\ M =/= U ) ) /\ ( # ` ( G NeighbVtx U ) ) = ( ( # ` V ) - 1 ) ) -> ( ( # ` ( G NeighbVtx U ) ) <_ ( ( # ` V ) - 2 ) <-> ( ( # ` V ) - 1 ) <_ ( ( # ` V ) - 2 ) ) ) |
17 |
1
|
fusgrvtxfi |
|- ( G e. FinUSGraph -> V e. Fin ) |
18 |
|
hashcl |
|- ( V e. Fin -> ( # ` V ) e. NN0 ) |
19 |
|
nn0re |
|- ( ( # ` V ) e. NN0 -> ( # ` V ) e. RR ) |
20 |
|
1red |
|- ( ( # ` V ) e. RR -> 1 e. RR ) |
21 |
|
2re |
|- 2 e. RR |
22 |
21
|
a1i |
|- ( ( # ` V ) e. RR -> 2 e. RR ) |
23 |
|
id |
|- ( ( # ` V ) e. RR -> ( # ` V ) e. RR ) |
24 |
|
1lt2 |
|- 1 < 2 |
25 |
24
|
a1i |
|- ( ( # ` V ) e. RR -> 1 < 2 ) |
26 |
20 22 23 25
|
ltsub2dd |
|- ( ( # ` V ) e. RR -> ( ( # ` V ) - 2 ) < ( ( # ` V ) - 1 ) ) |
27 |
23 22
|
resubcld |
|- ( ( # ` V ) e. RR -> ( ( # ` V ) - 2 ) e. RR ) |
28 |
|
peano2rem |
|- ( ( # ` V ) e. RR -> ( ( # ` V ) - 1 ) e. RR ) |
29 |
27 28
|
ltnled |
|- ( ( # ` V ) e. RR -> ( ( ( # ` V ) - 2 ) < ( ( # ` V ) - 1 ) <-> -. ( ( # ` V ) - 1 ) <_ ( ( # ` V ) - 2 ) ) ) |
30 |
26 29
|
mpbid |
|- ( ( # ` V ) e. RR -> -. ( ( # ` V ) - 1 ) <_ ( ( # ` V ) - 2 ) ) |
31 |
19 30
|
syl |
|- ( ( # ` V ) e. NN0 -> -. ( ( # ` V ) - 1 ) <_ ( ( # ` V ) - 2 ) ) |
32 |
17 18 31
|
3syl |
|- ( G e. FinUSGraph -> -. ( ( # ` V ) - 1 ) <_ ( ( # ` V ) - 2 ) ) |
33 |
32
|
pm2.21d |
|- ( G e. FinUSGraph -> ( ( ( # ` V ) - 1 ) <_ ( ( # ` V ) - 2 ) -> M e. ( G NeighbVtx U ) ) ) |
34 |
33
|
adantr |
|- ( ( G e. FinUSGraph /\ U e. V ) -> ( ( ( # ` V ) - 1 ) <_ ( ( # ` V ) - 2 ) -> M e. ( G NeighbVtx U ) ) ) |
35 |
34
|
ad3antlr |
|- ( ( ( ( -. M e. ( G NeighbVtx U ) /\ ( G e. FinUSGraph /\ U e. V ) ) /\ ( M e. V /\ M =/= U ) ) /\ ( # ` ( G NeighbVtx U ) ) = ( ( # ` V ) - 1 ) ) -> ( ( ( # ` V ) - 1 ) <_ ( ( # ` V ) - 2 ) -> M e. ( G NeighbVtx U ) ) ) |
36 |
16 35
|
sylbid |
|- ( ( ( ( -. M e. ( G NeighbVtx U ) /\ ( G e. FinUSGraph /\ U e. V ) ) /\ ( M e. V /\ M =/= U ) ) /\ ( # ` ( G NeighbVtx U ) ) = ( ( # ` V ) - 1 ) ) -> ( ( # ` ( G NeighbVtx U ) ) <_ ( ( # ` V ) - 2 ) -> M e. ( G NeighbVtx U ) ) ) |
37 |
36
|
ex |
|- ( ( ( -. M e. ( G NeighbVtx U ) /\ ( G e. FinUSGraph /\ U e. V ) ) /\ ( M e. V /\ M =/= U ) ) -> ( ( # ` ( G NeighbVtx U ) ) = ( ( # ` V ) - 1 ) -> ( ( # ` ( G NeighbVtx U ) ) <_ ( ( # ` V ) - 2 ) -> M e. ( G NeighbVtx U ) ) ) ) |
38 |
14 37
|
mpid |
|- ( ( ( -. M e. ( G NeighbVtx U ) /\ ( G e. FinUSGraph /\ U e. V ) ) /\ ( M e. V /\ M =/= U ) ) -> ( ( # ` ( G NeighbVtx U ) ) = ( ( # ` V ) - 1 ) -> M e. ( G NeighbVtx U ) ) ) |
39 |
38
|
ex |
|- ( ( -. M e. ( G NeighbVtx U ) /\ ( G e. FinUSGraph /\ U e. V ) ) -> ( ( M e. V /\ M =/= U ) -> ( ( # ` ( G NeighbVtx U ) ) = ( ( # ` V ) - 1 ) -> M e. ( G NeighbVtx U ) ) ) ) |
40 |
39
|
com23 |
|- ( ( -. M e. ( G NeighbVtx U ) /\ ( G e. FinUSGraph /\ U e. V ) ) -> ( ( # ` ( G NeighbVtx U ) ) = ( ( # ` V ) - 1 ) -> ( ( M e. V /\ M =/= U ) -> M e. ( G NeighbVtx U ) ) ) ) |
41 |
40
|
ex |
|- ( -. M e. ( G NeighbVtx U ) -> ( ( G e. FinUSGraph /\ U e. V ) -> ( ( # ` ( G NeighbVtx U ) ) = ( ( # ` V ) - 1 ) -> ( ( M e. V /\ M =/= U ) -> M e. ( G NeighbVtx U ) ) ) ) ) |
42 |
3 41
|
pm2.61i |
|- ( ( G e. FinUSGraph /\ U e. V ) -> ( ( # ` ( G NeighbVtx U ) ) = ( ( # ` V ) - 1 ) -> ( ( M e. V /\ M =/= U ) -> M e. ( G NeighbVtx U ) ) ) ) |