| Step |
Hyp |
Ref |
Expression |
| 1 |
|
mdslle1.1 |
|- A e. CH |
| 2 |
|
mdslle1.2 |
|- B e. CH |
| 3 |
|
mdslle1.3 |
|- C e. CH |
| 4 |
|
mdslle1.4 |
|- D e. CH |
| 5 |
3 4 1
|
chlej1i |
|- ( C C_ D -> ( C vH A ) C_ ( D vH A ) ) |
| 6 |
|
ssrin |
|- ( ( C vH A ) C_ ( D vH A ) -> ( ( C vH A ) i^i B ) C_ ( ( D vH A ) i^i B ) ) |
| 7 |
|
id |
|- ( A MH B -> A MH B ) |
| 8 |
|
ssin |
|- ( ( ( A i^i B ) C_ C /\ ( A i^i B ) C_ D ) <-> ( A i^i B ) C_ ( C i^i D ) ) |
| 9 |
8
|
bicomi |
|- ( ( A i^i B ) C_ ( C i^i D ) <-> ( ( A i^i B ) C_ C /\ ( A i^i B ) C_ D ) ) |
| 10 |
9
|
simplbi |
|- ( ( A i^i B ) C_ ( C i^i D ) -> ( A i^i B ) C_ C ) |
| 11 |
3 4 2
|
chlubi |
|- ( ( C C_ B /\ D C_ B ) <-> ( C vH D ) C_ B ) |
| 12 |
11
|
bicomi |
|- ( ( C vH D ) C_ B <-> ( C C_ B /\ D C_ B ) ) |
| 13 |
12
|
simplbi |
|- ( ( C vH D ) C_ B -> C C_ B ) |
| 14 |
1 2 3
|
3pm3.2i |
|- ( A e. CH /\ B e. CH /\ C e. CH ) |
| 15 |
|
mdsl3 |
|- ( ( ( A e. CH /\ B e. CH /\ C e. CH ) /\ ( A MH B /\ ( A i^i B ) C_ C /\ C C_ B ) ) -> ( ( C vH A ) i^i B ) = C ) |
| 16 |
14 15
|
mpan |
|- ( ( A MH B /\ ( A i^i B ) C_ C /\ C C_ B ) -> ( ( C vH A ) i^i B ) = C ) |
| 17 |
7 10 13 16
|
syl3an |
|- ( ( A MH B /\ ( A i^i B ) C_ ( C i^i D ) /\ ( C vH D ) C_ B ) -> ( ( C vH A ) i^i B ) = C ) |
| 18 |
9
|
simprbi |
|- ( ( A i^i B ) C_ ( C i^i D ) -> ( A i^i B ) C_ D ) |
| 19 |
12
|
simprbi |
|- ( ( C vH D ) C_ B -> D C_ B ) |
| 20 |
1 2 4
|
3pm3.2i |
|- ( A e. CH /\ B e. CH /\ D e. CH ) |
| 21 |
|
mdsl3 |
|- ( ( ( A e. CH /\ B e. CH /\ D e. CH ) /\ ( A MH B /\ ( A i^i B ) C_ D /\ D C_ B ) ) -> ( ( D vH A ) i^i B ) = D ) |
| 22 |
20 21
|
mpan |
|- ( ( A MH B /\ ( A i^i B ) C_ D /\ D C_ B ) -> ( ( D vH A ) i^i B ) = D ) |
| 23 |
7 18 19 22
|
syl3an |
|- ( ( A MH B /\ ( A i^i B ) C_ ( C i^i D ) /\ ( C vH D ) C_ B ) -> ( ( D vH A ) i^i B ) = D ) |
| 24 |
17 23
|
sseq12d |
|- ( ( A MH B /\ ( A i^i B ) C_ ( C i^i D ) /\ ( C vH D ) C_ B ) -> ( ( ( C vH A ) i^i B ) C_ ( ( D vH A ) i^i B ) <-> C C_ D ) ) |
| 25 |
6 24
|
imbitrid |
|- ( ( A MH B /\ ( A i^i B ) C_ ( C i^i D ) /\ ( C vH D ) C_ B ) -> ( ( C vH A ) C_ ( D vH A ) -> C C_ D ) ) |
| 26 |
5 25
|
impbid2 |
|- ( ( A MH B /\ ( A i^i B ) C_ ( C i^i D ) /\ ( C vH D ) C_ B ) -> ( C C_ D <-> ( C vH A ) C_ ( D vH A ) ) ) |