A regular language \(L\) is accepted by a non-deterministic finite automaton…

2025

A regular language \(L\) is accepted by a non-deterministic finite automaton (NFA) with \(n\) states. Which of the following statement(s) is/are FALSE?

  1. A.

    \(L\) may have an accepting NFA with  \(< n\) states

  2. B.

    \(L\) may have an accepting DFA with \(< n\) states.

  3. C.

    There exists a DFA with  \(≤ 2^n\) states that accepts \(L\).

  4. D.

    Every DFA that accepts \(L\) has  \(> 2^n\) states.

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Correct answer: D

Answer: Only the statement that every DFA accepting the language has more than 2^n states is false.

  • Statement about existence of an NFA with fewer than n states: Not universally false. Reason: The given NFA might not be minimal, so an equivalent NFA with fewer states can exist, though this is not guaranteed for every language.

  • Statement about existence of a DFA with fewer than n states: Not universally false. Reason: Some languages accepted by an n-state NFA may admit smaller DFAs, so this statement is possible but not guaranteed.

  • Statement that there exists a DFA with at most 2^n states: True. Reason: By the subset construction, every n-state NFA can be converted to an equivalent DFA whose states are subsets of the NFA states, giving at most 2^n DFA states.

  • Statement that every DFA accepting the language has more than 2^n states: False. Reason: The subset construction provides at least one DFA with at most 2^n states, so it cannot be true that every DFA requires more than 2^n states.

Conclusion: The only false statement is the claim that every DFA accepting the language has more than 2^n states.

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