| Step |
Hyp |
Ref |
Expression |
| 1 |
|
cnvco |
|- `' ( R o. S ) = ( `' S o. `' R ) |
| 2 |
|
cnvss |
|- ( ( R o. S ) C_ T -> `' ( R o. S ) C_ `' T ) |
| 3 |
1 2
|
eqsstrrid |
|- ( ( R o. S ) C_ T -> ( `' S o. `' R ) C_ `' T ) |
| 4 |
|
cnvco |
|- `' ( `' S o. `' R ) = ( `' `' R o. `' `' S ) |
| 5 |
|
cnvss |
|- ( ( `' S o. `' R ) C_ `' T -> `' ( `' S o. `' R ) C_ `' `' T ) |
| 6 |
|
sseq1 |
|- ( `' ( `' S o. `' R ) = ( `' `' R o. `' `' S ) -> ( `' ( `' S o. `' R ) C_ `' `' T <-> ( `' `' R o. `' `' S ) C_ `' `' T ) ) |
| 7 |
|
dfrel2 |
|- ( Rel R <-> `' `' R = R ) |
| 8 |
7
|
biimpi |
|- ( Rel R -> `' `' R = R ) |
| 9 |
8
|
3ad2ant1 |
|- ( ( Rel R /\ Rel S /\ Rel T ) -> `' `' R = R ) |
| 10 |
|
dfrel2 |
|- ( Rel S <-> `' `' S = S ) |
| 11 |
10
|
biimpi |
|- ( Rel S -> `' `' S = S ) |
| 12 |
11
|
3ad2ant2 |
|- ( ( Rel R /\ Rel S /\ Rel T ) -> `' `' S = S ) |
| 13 |
9 12
|
coeq12d |
|- ( ( Rel R /\ Rel S /\ Rel T ) -> ( `' `' R o. `' `' S ) = ( R o. S ) ) |
| 14 |
|
dfrel2 |
|- ( Rel T <-> `' `' T = T ) |
| 15 |
14
|
biimpi |
|- ( Rel T -> `' `' T = T ) |
| 16 |
15
|
3ad2ant3 |
|- ( ( Rel R /\ Rel S /\ Rel T ) -> `' `' T = T ) |
| 17 |
13 16
|
sseq12d |
|- ( ( Rel R /\ Rel S /\ Rel T ) -> ( ( `' `' R o. `' `' S ) C_ `' `' T <-> ( R o. S ) C_ T ) ) |
| 18 |
17
|
biimpcd |
|- ( ( `' `' R o. `' `' S ) C_ `' `' T -> ( ( Rel R /\ Rel S /\ Rel T ) -> ( R o. S ) C_ T ) ) |
| 19 |
6 18
|
biimtrdi |
|- ( `' ( `' S o. `' R ) = ( `' `' R o. `' `' S ) -> ( `' ( `' S o. `' R ) C_ `' `' T -> ( ( Rel R /\ Rel S /\ Rel T ) -> ( R o. S ) C_ T ) ) ) |
| 20 |
4 5 19
|
mpsyl |
|- ( ( `' S o. `' R ) C_ `' T -> ( ( Rel R /\ Rel S /\ Rel T ) -> ( R o. S ) C_ T ) ) |
| 21 |
20
|
com12 |
|- ( ( Rel R /\ Rel S /\ Rel T ) -> ( ( `' S o. `' R ) C_ `' T -> ( R o. S ) C_ T ) ) |
| 22 |
3 21
|
impbid2 |
|- ( ( Rel R /\ Rel S /\ Rel T ) -> ( ( R o. S ) C_ T <-> ( `' S o. `' R ) C_ `' T ) ) |