A

Turing Machine that is

deterministic, i.e. that for every

state and

symbol, there is ONE action the machine will do. Its

transition function is deterministic.

A DTM is defined by a 7-tuple:
(Q, E, L, d, q_{start}, q_{accept}, q_{reject}), where:

- Q is the set of states
- E is the input alphabet, not containing the symbols '_' (space) and ">" (beginning of the tape).
- L is the tape alphabet, so L = E U {_} U {>}.
- d is the transition function. d: Q * L -> Q * L * {L,R}, where L and R indicate the head moves left or right, respectively.
- q
_{start}, q_{accept} and q_{reject} are memebers of Q

See also Non Deterministic Turing Machine.