Question
Download Solution PDFWhich of the following problems is undecidable ?
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFThe correct answer is Ambiguity problem for CFGs.
Key Points
- The Ambiguity problem for CFGs (Context-Free Grammars) is undecidable.
- A context-free grammar is ambiguous if there exists a string that can be generated by the grammar in more than one way (i.e., it has more than one distinct parse tree).
- The ambiguity problem asks whether a given CFG is ambiguous.
- This problem is undecidable, meaning there is no algorithm that can determine the ambiguity of any CFG in general.
Additional Information
- Other problems listed in the options are decidable:
- The membership problem for CFGs is decidable. This problem asks whether a given string can be generated by a CFG.
- The finiteness problem for FSAs (Finite State Automata) is decidable. This problem asks whether the language recognized by the FSA is finite.
- The equivalence problem for FSAs is decidable. This problem asks whether two FSAs recognize the same language.
Last updated on Jun 26, 2025
-> NIELIT Scientific Assistant admit card 2025 has been released.
-> NIELIT Scientific Assistant city intimation slip 2025 has been released at the official website.
-> NIELIT Scientific Assistant exam 2025 is scheduled to be conducted on June 28.
-> A total number of 113 revised vacancies have been announced for the post of Scientific Assistant in Computer Science (CS), Information Technology (IT), and Electronics & Communication (EC) streams.
-> Online application form, last date has been extended up to from 17th April 2025.
->The NIELT has revised the Essential Qualifications for the post of Scientific Assistant. Candidates must possess (M.Sc.)/ (MS)/ (MCA) / (B.E.)/ (B.Tech) in relevant disciplines.
-> The NIELIT Scientific Assistant 2025 Notification has been released by the National Institute of Electronics and Information Technology (NIELIT).