Which of the following pairs have DIFFERENT expressive power?
(A) Deterministic finite automata(DFA) and Non-deterministic finite automata(NFA)
(B) Deterministic push down automata(DPDA)and Non-deterministic push down automata(NPDA)
(C) Deterministic single-tape Turing machine and Non-deterministic single-tape Turing machine
(D) Single-tape Turing machine and multi-tape Turing machine
Answer: (B)
Explanation:
NDPDA can handle languages or grammars with ambiguity, but DPDA cannot handle languages with ambiguity and any context-free grammar.