Let L1 be a recursive language. Let L2 and L3 be languages that are recursively enumerable but not recursive. Which of the following statements is not necessarily true?

Related MCQs

• Consider the following statements I. Recursive languages are closed under complementation II. Recursively enumerable languages are closed under union III. Recursively enumerable languages are closed under complementation Which of the above statement are TRUE?
• Let L1 be a recursive language, and let L2 be a recursively enumerable but not a recursive language. Which one of the following is TRUE?
• Recursively enumerable languages are not closed under
• Recursively enumerable languages are not closed under:
• Recursively enumerable languages are not closed under
• Which of the following statements is/are FALSE? (1) For every non-deterministic Turing machine, there exists an equivalent deterministic Turing machine. (2) Turing recognizable languages are closed under union and complementation. (3) Turing decidable languages are closed under intersection and complementation (4) Turing recognizable languages are closed under union and intersection.
• If L and L¯ are recursively enumerable, then L is
• If L1 and L2 are context free language and R a regular set, then which one of the languages below is not necessarily a context free language?
• Consider the NFA M shown below. Let the language accepted by M be L. Let L1 be the language accepted by the NFA M1, obtained by changing the accepting state of M to a non-accepting state and by changing the non-accepting state of M to accepting states. Which of the following statements is true?
• Let P be a regular language and Q be context-free language such that Q ∈ P. (For example, let P be the language represented by the regular expression p*q* and Q be {pnqn n∈ N}). Then which of the following is ALWAYS regular?