Which of the following decision problems are undescidable?
I. Given NFAs N1 and N2, is L(N1)∩L(N2)=ϕ
II. Given a CFG G = (N, ∑, P, S) and a string xϵ∑∗, does xϵL(G)?
III. Given CFGs G1andG2, is L(G1)=L(G2) ?
IV. Given a TM M, is L(M)=ϕ ?