Description: A Tseitin axiom for logical conjunction, in deduction form. (Contributed by Giovanni Mascellani, 24-Mar-2018)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | tsan3 | |- ( th -> ( ps \/ -. ( ph /\ ps ) ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | pm3.14 | |- ( ( -. ph \/ -. ps ) -> -. ( ph /\ ps ) ) | |
| 2 | 1 | olcs | |- ( -. ps -> -. ( ph /\ ps ) ) | 
| 3 | 2 | orri | |- ( ps \/ -. ( ph /\ ps ) ) | 
| 4 | 3 | a1i | |- ( th -> ( ps \/ -. ( ph /\ ps ) ) ) |