| Step |
Hyp |
Ref |
Expression |
| 1 |
|
ishil2.v |
|- V = ( Base ` H ) |
| 2 |
|
ishil2.s |
|- .(+) = ( LSSum ` H ) |
| 3 |
|
ishil2.o |
|- ._|_ = ( ocv ` H ) |
| 4 |
|
ishil2.c |
|- C = ( ClSubSp ` H ) |
| 5 |
|
eqid |
|- ( proj ` H ) = ( proj ` H ) |
| 6 |
5 4
|
ishil |
|- ( H e. Hil <-> ( H e. PreHil /\ dom ( proj ` H ) = C ) ) |
| 7 |
5 4
|
pjcss |
|- ( H e. PreHil -> dom ( proj ` H ) C_ C ) |
| 8 |
|
eqss |
|- ( dom ( proj ` H ) = C <-> ( dom ( proj ` H ) C_ C /\ C C_ dom ( proj ` H ) ) ) |
| 9 |
8
|
baib |
|- ( dom ( proj ` H ) C_ C -> ( dom ( proj ` H ) = C <-> C C_ dom ( proj ` H ) ) ) |
| 10 |
7 9
|
syl |
|- ( H e. PreHil -> ( dom ( proj ` H ) = C <-> C C_ dom ( proj ` H ) ) ) |
| 11 |
|
dfss3 |
|- ( C C_ dom ( proj ` H ) <-> A. s e. C s e. dom ( proj ` H ) ) |
| 12 |
10 11
|
bitrdi |
|- ( H e. PreHil -> ( dom ( proj ` H ) = C <-> A. s e. C s e. dom ( proj ` H ) ) ) |
| 13 |
|
eqid |
|- ( LSubSp ` H ) = ( LSubSp ` H ) |
| 14 |
4 13
|
csslss |
|- ( ( H e. PreHil /\ s e. C ) -> s e. ( LSubSp ` H ) ) |
| 15 |
1 13 3 2 5
|
pjdm2 |
|- ( H e. PreHil -> ( s e. dom ( proj ` H ) <-> ( s e. ( LSubSp ` H ) /\ ( s .(+) ( ._|_ ` s ) ) = V ) ) ) |
| 16 |
15
|
baibd |
|- ( ( H e. PreHil /\ s e. ( LSubSp ` H ) ) -> ( s e. dom ( proj ` H ) <-> ( s .(+) ( ._|_ ` s ) ) = V ) ) |
| 17 |
14 16
|
syldan |
|- ( ( H e. PreHil /\ s e. C ) -> ( s e. dom ( proj ` H ) <-> ( s .(+) ( ._|_ ` s ) ) = V ) ) |
| 18 |
17
|
ralbidva |
|- ( H e. PreHil -> ( A. s e. C s e. dom ( proj ` H ) <-> A. s e. C ( s .(+) ( ._|_ ` s ) ) = V ) ) |
| 19 |
12 18
|
bitrd |
|- ( H e. PreHil -> ( dom ( proj ` H ) = C <-> A. s e. C ( s .(+) ( ._|_ ` s ) ) = V ) ) |
| 20 |
19
|
pm5.32i |
|- ( ( H e. PreHil /\ dom ( proj ` H ) = C ) <-> ( H e. PreHil /\ A. s e. C ( s .(+) ( ._|_ ` s ) ) = V ) ) |
| 21 |
6 20
|
bitri |
|- ( H e. Hil <-> ( H e. PreHil /\ A. s e. C ( s .(+) ( ._|_ ` s ) ) = V ) ) |