| Step |
Hyp |
Ref |
Expression |
| 1 |
|
ifpidg |
|- ( ( ps <-> if- ( ph , ps , ch ) ) <-> ( ( ( ( ph /\ ps ) -> ps ) /\ ( ( ph /\ ps ) -> ps ) ) /\ ( ( ch -> ( ph \/ ps ) ) /\ ( ps -> ( ph \/ ch ) ) ) ) ) |
| 2 |
|
simpr |
|- ( ( ph /\ ps ) -> ps ) |
| 3 |
2 2
|
pm3.2i |
|- ( ( ( ph /\ ps ) -> ps ) /\ ( ( ph /\ ps ) -> ps ) ) |
| 4 |
3
|
biantrur |
|- ( ( ( ch -> ( ph \/ ps ) ) /\ ( ps -> ( ph \/ ch ) ) ) <-> ( ( ( ( ph /\ ps ) -> ps ) /\ ( ( ph /\ ps ) -> ps ) ) /\ ( ( ch -> ( ph \/ ps ) ) /\ ( ps -> ( ph \/ ch ) ) ) ) ) |
| 5 |
|
ancom |
|- ( ( ( ch -> ( ph \/ ps ) ) /\ ( ps -> ( ph \/ ch ) ) ) <-> ( ( ps -> ( ph \/ ch ) ) /\ ( ch -> ( ph \/ ps ) ) ) ) |
| 6 |
1 4 5
|
3bitr2i |
|- ( ( ps <-> if- ( ph , ps , ch ) ) <-> ( ( ps -> ( ph \/ ch ) ) /\ ( ch -> ( ph \/ ps ) ) ) ) |