| Step |
Hyp |
Ref |
Expression |
| 1 |
|
sstr2 |
|- ( A C_ B -> ( B C_ x -> A C_ x ) ) |
| 2 |
1
|
adantr |
|- ( ( A C_ B /\ x e. SH ) -> ( B C_ x -> A C_ x ) ) |
| 3 |
2
|
ss2rabdv |
|- ( A C_ B -> { x e. SH | B C_ x } C_ { x e. SH | A C_ x } ) |
| 4 |
|
intss |
|- ( { x e. SH | B C_ x } C_ { x e. SH | A C_ x } -> |^| { x e. SH | A C_ x } C_ |^| { x e. SH | B C_ x } ) |
| 5 |
3 4
|
syl |
|- ( A C_ B -> |^| { x e. SH | A C_ x } C_ |^| { x e. SH | B C_ x } ) |
| 6 |
5
|
adantl |
|- ( ( B C_ ~H /\ A C_ B ) -> |^| { x e. SH | A C_ x } C_ |^| { x e. SH | B C_ x } ) |
| 7 |
|
sstr |
|- ( ( A C_ B /\ B C_ ~H ) -> A C_ ~H ) |
| 8 |
7
|
ancoms |
|- ( ( B C_ ~H /\ A C_ B ) -> A C_ ~H ) |
| 9 |
|
spanval |
|- ( A C_ ~H -> ( span ` A ) = |^| { x e. SH | A C_ x } ) |
| 10 |
8 9
|
syl |
|- ( ( B C_ ~H /\ A C_ B ) -> ( span ` A ) = |^| { x e. SH | A C_ x } ) |
| 11 |
|
spanval |
|- ( B C_ ~H -> ( span ` B ) = |^| { x e. SH | B C_ x } ) |
| 12 |
11
|
adantr |
|- ( ( B C_ ~H /\ A C_ B ) -> ( span ` B ) = |^| { x e. SH | B C_ x } ) |
| 13 |
6 10 12
|
3sstr4d |
|- ( ( B C_ ~H /\ A C_ B ) -> ( span ` A ) C_ ( span ` B ) ) |