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Questions related to computability theory, a.k.a. recursion theory

-1 votes

Decidability. $\lbrace \langle D \rangle \mid \text{$D$ accepts $a^kb^k$ for some $k > 0$}\r...

Corollary 3.19 from "An Introduction to the Theory of Computation": "A language is decidable if and only if some nondeterministic Turing machine decides it." You can construct a nondeterministic Turi …
Pétur Ingi Egilsson's user avatar
0 votes

Can a Turing machine decide the language $L_\emptyset$ of machines with empty language?

Proof by contradicting $A_{TM}= \{\langle M,w\rangle \mid M \text{ is a Turing Machine which accepts w}\}$, (which we know is undecidable). Assume the existence of $R_{TM}$, a TM that decides $L_\emp …
Pétur Ingi Egilsson's user avatar