Can some one please help me with below problem :

Compute the existential predecessors of the state set specified by the propositional logic formula p ∧ ¬q symbolically. Perform the computation on the corresponding Kripke structure. Convert your result to a quantifier-free formula in DNF (recall: ϕR = a ∧ ((p ∧ q) ↔ ¬p 0 ) ∧ (q 0 ↔ (¬p ∧ ¬q))).