Rice's theorem for language properties
Every nontrivial property of the language recognized by a Turing machine is undecidable from its machine description.
Key knowledge
Every nontrivial property of the language recognized by a Turing machine is undecidable from its machine description. Nontrivial means some recognizable language has the property and another does not; machine-syntax properties are outside this theorem.
Conditions and scope
- The property must depend only on the recognized language.
- Undecidability does not automatically imply nonrecognizability.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Lecture 9 Rice statement, slides 31–32 and applicability counterexamples, slides 38–45.
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