Question: pda can be converted to cfg?
Answer: Take a PDA M=(Q,Σ,Γ,δ,q0,Z0,∅) that accepts L=N(M) by empty stack (if you have a PDA accepting by final state, first convert to empty stack). We define a CFG that accepts L. The nonterminals are symbols of the form [p,A,q] with p,q∈Q, A∈Γ, and a start symbol S.