| Step |
Hyp |
Ref |
Expression |
| 1 |
|
dprdf1.1 |
|- ( ph -> G dom DProd S ) |
| 2 |
|
dprdf1.2 |
|- ( ph -> dom S = I ) |
| 3 |
|
dprdf1.3 |
|- ( ph -> F : J -1-1-> I ) |
| 4 |
|
f1f |
|- ( F : J -1-1-> I -> F : J --> I ) |
| 5 |
|
frn |
|- ( F : J --> I -> ran F C_ I ) |
| 6 |
3 4 5
|
3syl |
|- ( ph -> ran F C_ I ) |
| 7 |
1 2 6
|
dprdres |
|- ( ph -> ( G dom DProd ( S |` ran F ) /\ ( G DProd ( S |` ran F ) ) C_ ( G DProd S ) ) ) |
| 8 |
7
|
simpld |
|- ( ph -> G dom DProd ( S |` ran F ) ) |
| 9 |
1 2
|
dprdf2 |
|- ( ph -> S : I --> ( SubGrp ` G ) ) |
| 10 |
9 6
|
fssresd |
|- ( ph -> ( S |` ran F ) : ran F --> ( SubGrp ` G ) ) |
| 11 |
10
|
fdmd |
|- ( ph -> dom ( S |` ran F ) = ran F ) |
| 12 |
|
f1f1orn |
|- ( F : J -1-1-> I -> F : J -1-1-onto-> ran F ) |
| 13 |
3 12
|
syl |
|- ( ph -> F : J -1-1-onto-> ran F ) |
| 14 |
8 11 13
|
dprdf1o |
|- ( ph -> ( G dom DProd ( ( S |` ran F ) o. F ) /\ ( G DProd ( ( S |` ran F ) o. F ) ) = ( G DProd ( S |` ran F ) ) ) ) |
| 15 |
14
|
simpld |
|- ( ph -> G dom DProd ( ( S |` ran F ) o. F ) ) |
| 16 |
|
ssid |
|- ran F C_ ran F |
| 17 |
|
cores |
|- ( ran F C_ ran F -> ( ( S |` ran F ) o. F ) = ( S o. F ) ) |
| 18 |
16 17
|
ax-mp |
|- ( ( S |` ran F ) o. F ) = ( S o. F ) |
| 19 |
15 18
|
breqtrdi |
|- ( ph -> G dom DProd ( S o. F ) ) |
| 20 |
18
|
oveq2i |
|- ( G DProd ( ( S |` ran F ) o. F ) ) = ( G DProd ( S o. F ) ) |
| 21 |
14
|
simprd |
|- ( ph -> ( G DProd ( ( S |` ran F ) o. F ) ) = ( G DProd ( S |` ran F ) ) ) |
| 22 |
20 21
|
eqtr3id |
|- ( ph -> ( G DProd ( S o. F ) ) = ( G DProd ( S |` ran F ) ) ) |
| 23 |
7
|
simprd |
|- ( ph -> ( G DProd ( S |` ran F ) ) C_ ( G DProd S ) ) |
| 24 |
22 23
|
eqsstrd |
|- ( ph -> ( G DProd ( S o. F ) ) C_ ( G DProd S ) ) |
| 25 |
19 24
|
jca |
|- ( ph -> ( G dom DProd ( S o. F ) /\ ( G DProd ( S o. F ) ) C_ ( G DProd S ) ) ) |