Lecture 28
Section outline
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December 12th, Tuesday (12:30-14:30)
Undecidability
- Diagonalization language \( L_d \)
- Properties of recursive languages
- Properties of RE languages
- Universal Language \( L_u \)
- Universal TM \( U \)
- \( L_u \) is in RE
- \( L_u \) is not in REC (\(L_d \leq_m \overline{L_u}\))
- Halting problem for a TM on a given input
References
- Hopcroft et al., chapter 9