Q is the symbol for the set of states
q is the symbol for the start state.
The state that the automaton <math>A</math> is in after processing input <math>w</math> is expressed by the below expression: <MATH>\delta(A,w)</MATH>
where: <math>\delta</math> is a symbol for a transition function
in one of this state, the automaton will operate:
Entering one of these states after a sequence of inputs indicates that the input sequence is good in some way
It is conventional to designate accepting states by a double circle