| Step |
Hyp |
Ref |
Expression |
| 1 |
|
osum.1 |
|- A e. CH |
| 2 |
|
osum.2 |
|- B e. CH |
| 3 |
1 2
|
cmcm2i |
|- ( A C_H B <-> A C_H ( _|_ ` B ) ) |
| 4 |
2
|
choccli |
|- ( _|_ ` B ) e. CH |
| 5 |
1 4
|
cmbr4i |
|- ( A C_H ( _|_ ` B ) <-> ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) C_ ( _|_ ` B ) ) |
| 6 |
3 5
|
bitri |
|- ( A C_H B <-> ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) C_ ( _|_ ` B ) ) |
| 7 |
1
|
choccli |
|- ( _|_ ` A ) e. CH |
| 8 |
7 4
|
chjcli |
|- ( ( _|_ ` A ) vH ( _|_ ` B ) ) e. CH |
| 9 |
1 8
|
chincli |
|- ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) e. CH |
| 10 |
9 2
|
osumi |
|- ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) C_ ( _|_ ` B ) -> ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) +H B ) = ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) vH B ) ) |
| 11 |
7 4
|
chjcomi |
|- ( ( _|_ ` A ) vH ( _|_ ` B ) ) = ( ( _|_ ` B ) vH ( _|_ ` A ) ) |
| 12 |
11
|
ineq2i |
|- ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) = ( A i^i ( ( _|_ ` B ) vH ( _|_ ` A ) ) ) |
| 13 |
12
|
oveq1i |
|- ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) vH B ) = ( ( A i^i ( ( _|_ ` B ) vH ( _|_ ` A ) ) ) vH B ) |
| 14 |
4 7
|
chjcli |
|- ( ( _|_ ` B ) vH ( _|_ ` A ) ) e. CH |
| 15 |
1 14
|
chincli |
|- ( A i^i ( ( _|_ ` B ) vH ( _|_ ` A ) ) ) e. CH |
| 16 |
15 2
|
chjcomi |
|- ( ( A i^i ( ( _|_ ` B ) vH ( _|_ ` A ) ) ) vH B ) = ( B vH ( A i^i ( ( _|_ ` B ) vH ( _|_ ` A ) ) ) ) |
| 17 |
13 16
|
eqtri |
|- ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) vH B ) = ( B vH ( A i^i ( ( _|_ ` B ) vH ( _|_ ` A ) ) ) ) |
| 18 |
2 1
|
pjoml4i |
|- ( B vH ( A i^i ( ( _|_ ` B ) vH ( _|_ ` A ) ) ) ) = ( B vH A ) |
| 19 |
2 1
|
chjcomi |
|- ( B vH A ) = ( A vH B ) |
| 20 |
18 19
|
eqtri |
|- ( B vH ( A i^i ( ( _|_ ` B ) vH ( _|_ ` A ) ) ) ) = ( A vH B ) |
| 21 |
17 20
|
eqtri |
|- ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) vH B ) = ( A vH B ) |
| 22 |
21
|
eqeq2i |
|- ( ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) +H B ) = ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) vH B ) <-> ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) +H B ) = ( A vH B ) ) |
| 23 |
|
inss1 |
|- ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) C_ A |
| 24 |
9
|
chshii |
|- ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) e. SH |
| 25 |
1
|
chshii |
|- A e. SH |
| 26 |
2
|
chshii |
|- B e. SH |
| 27 |
24 25 26
|
shlessi |
|- ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) C_ A -> ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) +H B ) C_ ( A +H B ) ) |
| 28 |
23 27
|
ax-mp |
|- ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) +H B ) C_ ( A +H B ) |
| 29 |
|
sseq1 |
|- ( ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) +H B ) = ( A vH B ) -> ( ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) +H B ) C_ ( A +H B ) <-> ( A vH B ) C_ ( A +H B ) ) ) |
| 30 |
28 29
|
mpbii |
|- ( ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) +H B ) = ( A vH B ) -> ( A vH B ) C_ ( A +H B ) ) |
| 31 |
22 30
|
sylbi |
|- ( ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) +H B ) = ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) vH B ) -> ( A vH B ) C_ ( A +H B ) ) |
| 32 |
10 31
|
syl |
|- ( ( A i^i ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) C_ ( _|_ ` B ) -> ( A vH B ) C_ ( A +H B ) ) |
| 33 |
6 32
|
sylbi |
|- ( A C_H B -> ( A vH B ) C_ ( A +H B ) ) |
| 34 |
1 2
|
chsleji |
|- ( A +H B ) C_ ( A vH B ) |
| 35 |
33 34
|
jctil |
|- ( A C_H B -> ( ( A +H B ) C_ ( A vH B ) /\ ( A vH B ) C_ ( A +H B ) ) ) |
| 36 |
|
eqss |
|- ( ( A +H B ) = ( A vH B ) <-> ( ( A +H B ) C_ ( A vH B ) /\ ( A vH B ) C_ ( A +H B ) ) ) |
| 37 |
35 36
|
sylibr |
|- ( A C_H B -> ( A +H B ) = ( A vH B ) ) |