Step |
Hyp |
Ref |
Expression |
1 |
|
strlem3.1 |
|- S = ( x e. CH |-> ( ( normh ` ( ( projh ` x ) ` u ) ) ^ 2 ) ) |
2 |
|
strlem3.2 |
|- ( ph <-> ( u e. ( A \ B ) /\ ( normh ` u ) = 1 ) ) |
3 |
|
strlem3.3 |
|- A e. CH |
4 |
|
strlem3.4 |
|- B e. CH |
5 |
1
|
strlem2 |
|- ( A e. CH -> ( S ` A ) = ( ( normh ` ( ( projh ` A ) ` u ) ) ^ 2 ) ) |
6 |
3 5
|
ax-mp |
|- ( S ` A ) = ( ( normh ` ( ( projh ` A ) ` u ) ) ^ 2 ) |
7 |
|
eldifi |
|- ( u e. ( A \ B ) -> u e. A ) |
8 |
|
pjid |
|- ( ( A e. CH /\ u e. A ) -> ( ( projh ` A ) ` u ) = u ) |
9 |
3 8
|
mpan |
|- ( u e. A -> ( ( projh ` A ) ` u ) = u ) |
10 |
9
|
fveq2d |
|- ( u e. A -> ( normh ` ( ( projh ` A ) ` u ) ) = ( normh ` u ) ) |
11 |
|
eqeq2 |
|- ( ( normh ` u ) = 1 -> ( ( normh ` ( ( projh ` A ) ` u ) ) = ( normh ` u ) <-> ( normh ` ( ( projh ` A ) ` u ) ) = 1 ) ) |
12 |
10 11
|
syl5ib |
|- ( ( normh ` u ) = 1 -> ( u e. A -> ( normh ` ( ( projh ` A ) ` u ) ) = 1 ) ) |
13 |
7 12
|
mpan9 |
|- ( ( u e. ( A \ B ) /\ ( normh ` u ) = 1 ) -> ( normh ` ( ( projh ` A ) ` u ) ) = 1 ) |
14 |
2 13
|
sylbi |
|- ( ph -> ( normh ` ( ( projh ` A ) ` u ) ) = 1 ) |
15 |
14
|
oveq1d |
|- ( ph -> ( ( normh ` ( ( projh ` A ) ` u ) ) ^ 2 ) = ( 1 ^ 2 ) ) |
16 |
|
sq1 |
|- ( 1 ^ 2 ) = 1 |
17 |
15 16
|
eqtrdi |
|- ( ph -> ( ( normh ` ( ( projh ` A ) ` u ) ) ^ 2 ) = 1 ) |
18 |
6 17
|
eqtrid |
|- ( ph -> ( S ` A ) = 1 ) |