Step |
Hyp |
Ref |
Expression |
1 |
|
pm5.53 |
|- ( ( ( ( ph \/ ch ) \/ th ) -> ps ) <-> ( ( ( ph -> ps ) /\ ( ch -> ps ) ) /\ ( th -> ps ) ) ) |
2 |
|
df-3or |
|- ( ( ph \/ ch \/ th ) <-> ( ( ph \/ ch ) \/ th ) ) |
3 |
2
|
imbi1i |
|- ( ( ( ph \/ ch \/ th ) -> ps ) <-> ( ( ( ph \/ ch ) \/ th ) -> ps ) ) |
4 |
|
df-3an |
|- ( ( ( ph -> ps ) /\ ( ch -> ps ) /\ ( th -> ps ) ) <-> ( ( ( ph -> ps ) /\ ( ch -> ps ) ) /\ ( th -> ps ) ) ) |
5 |
1 3 4
|
3bitr4i |
|- ( ( ( ph \/ ch \/ th ) -> ps ) <-> ( ( ph -> ps ) /\ ( ch -> ps ) /\ ( th -> ps ) ) ) |