1. P v Q, ~(P & Q) |- P <->
~Q
2. P & Q |- P <-> Q
3. Q -> R, ~P -> S, Q v
S |- S v (R & P)
4. P v Q, Q -> R, ~R v S |- ~S
-> P
5. (P v Q) & (Q -> R) |- P
v R
6. P <-> ~Q & S, P &
(~T -> ~S) |- ~Q & T
7. (P -> Q) -> R, S -> (~Q -> T)
|- R v ~T -> (S -> R)
8. P & Q -> R |- P & ~R
-> ~Q
9. P & (Q <-> R) |- P &
Q <-> R
10. ~(P & Q), Q v ~S |- S ->
~P
11. ~P -> Q, Q -> ~R |- R -> P
12. P <-> S, Q v P, Q -> R |- S v R