Accessibility properties can be checked on any type of (weighted) automaton
or transducer.
- A state s of an automaton is
-
accessible if there exists a path from an initial state to s;
the weights of the transitions are never considered for accessibility; for
instance, if the semiring is not integral, the weight of every path from an
initial state to an accessible state may be zero;
-
coaccessible if there exists a path from s to a final
state to s;
-
useful if it is both accessible and coaccessible;
- An automaton A is
-
accessible if every state of A is accessible;
-
coaccessible if every state of A is coaccessible;
- trim if every state of A is trim.