GATE CS 2025 Set 1 — Question 28
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Theory of Computation → Finite Automata & Regular Languages → NFA to DFA (Subset Construction)
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Question
A regular language is accepted by a non-deterministic finite automaton (NFA) with states. Which of the following statement(s) is/are FALSE?
Correct answer
(D) Every DFA that accepts L has 2ⁿ states.
Solution
Analysis of the statements regarding a regular language accepted by an -state NFA:
1.Statement (A): " may have an accepting NFA with states."
This is true. If the given -state NFA is not the minimal NFA for the language , then there exists a smaller NFA that accepts the same language.2.Statement (B): " may have an accepting DFA with states."
This is true. For certain languages, the minimal DFA can have fewer states than a given non-minimal NFA. For example, an NFA with 2 states for the language can be simplified to a DFA with only 1 state.3.Statement (C): "There exists a DFA with states that accepts ."
This is true. According to the powerset construction (or subset construction) algorithm, any NFA with states can be converted into an equivalent DFA with at most states.4.Statement (D): "Every DFA that accepts has states."
This is false. It directly contradicts statement (C). Since we know there exists at least one DFA (from the subset construction) with states, it is impossible for every DFA to have more than states.Since the question asks for the FALSE statement(s), only (D) is the correct choice.Continue learning with Success Tracker
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