A Characterization of the Chomsky Hierarchy by String Turing Machines
نویسنده
چکیده
A string Turing machine is a variant of a Turing machine designed for easy manipulation of strings. In contrast to the standard Turing machine, a string Turing machine can insert and delete squares on the tape. It is easy to see that the models of standard and string Turing machines are equivalent in computing power. However, in case of the string Turing machine, imposing certain restrictions on the allowed actions of the machine exactly yields recognizers for the type-i language classes of the Chomsky hierarchy.
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