Does [^aeiou][aeiou][^aeiou]
match bat?
Yes, as well as rat, dog, fog and many other strings.
The above automaton corresponds to the
regular expression [a-z][^0-9]
.
The transition from state q1 to q2
should properly be labeled with all the characters that can
cause that transition.
However, if the alphabet consists of all ASCII characters,
the transition would be labeled with too many characters.
It is just as easy to label it with part of a regular expression.
However, recall that the transition from state q1 to q2 eats just one character.
Does the above automaton (and regular expression) match the string b# ?