Since P → Q and P → ¬Q are WFFs, ( P → Q) ( P → ¬Q) is a WFF.Since P, Q, and ¬Q are WFFs, P → Q and P → ¬Q are WFFs.Since ( P ¬Q) ( Q ¬P ) and ¬( P ↔ Q) are WFFs, (( P ¬Q) ( Q ¬P )) → ¬( P ↔ Q) is a WFF.ĪPPENDIX C.Since P ¬Q and Q ¬P are WFFs, ( P ¬Q) ( Q ¬P ) is a WFF.Since P ↔ Q is a WFF, ¬( P ↔ Q) is a WFF.Since P and Q are WFFs, P ↔ Q is a WFF.Since P, Q, ¬P and ¬Q are WFFs, P ¬Q and Q ¬P are WFFs.Since P and Q are WFFs, ¬P and ¬Q are WFFs.The proposition is satisfiable but not a tautology. Since ( P Q) ( P R) and P ( Q R) are WFFs, ( P Q) ( P R) ↔ P ( Q R) is a WFF.Since P Q and P R are WFFs, ( P Q) ( P R) is a WFF.
