Description: Restate implication as conditional logic operator. (Contributed by RP, 20-Apr-2020)
Ref | Expression | ||
---|---|---|---|
Assertion | ifpim1 | |- ( ( ph -> ps ) <-> if- ( -. ph , T. , ps ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | tru | |- T. |
|
2 | 1 | olci | |- ( -. -. ph \/ T. ) |
3 | 2 | biantrur | |- ( ( -. ph \/ ps ) <-> ( ( -. -. ph \/ T. ) /\ ( -. ph \/ ps ) ) ) |
4 | imor | |- ( ( ph -> ps ) <-> ( -. ph \/ ps ) ) |
|
5 | dfifp4 | |- ( if- ( -. ph , T. , ps ) <-> ( ( -. -. ph \/ T. ) /\ ( -. ph \/ ps ) ) ) |
|
6 | 3 4 5 | 3bitr4i | |- ( ( ph -> ps ) <-> if- ( -. ph , T. , ps ) ) |