Metamath Proof Explorer


Theorem tsan3

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 ) ) )

Proof

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 ) ) )