- Q is a set of states,
- is a finite set of
symbols, the
*input alphabet,* - is a finite set of
symbols, the
*tape alphabet,* - is the
*partial*transition function, - #
is a symbol called
*blank*, - q
_{0}Q is the initial state, - F Q is a set of final states.

- The tape is initially
*blank*(every symbol is #) except possibly for a finite, contiguous sequence of symbols. - If there are initially nonblank symbols on the tape, the tape head is initially positioned on one of them.

Most other textbooks make no distinction between (the input alphabet) and (the tape alphabet). Our textbook does this to emphasize that the "input" (the nonblank symbols on the tape) does not contain #. Also, there may be more symbols in than are present in the input.

Copyright © 1996 by David Matuszek

Last modified Mar 24, 1996