Recognizability versus decidability
A recognizer accepts every member of its language but may run forever on a nonmember.
Key knowledge
A recognizer accepts every member of its language but may run forever on a nonmember. A decider halts on every input with the correct answer. A language is decidable exactly when it and its complement are both Turing-recognizable.
Conditions and scope
- Run the two recognizers by interleaving steps rather than waiting for one to finish.
- All regular languages are decidable.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Lecture 7 definitions and Theorem 4 dovetailing proof, slides 4–10.
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Entry details
Permanent link to this entry ↗- Record identity
- info-recognizers-and-deciders
- Revision
- university-core.1
- Structured reference record
- University core expansion