1
$\begingroup$

Is there a DFA that accepts no string, but has at least one final state?

I think it would be possible to make a DFA that accepts no string only by creating no final states or by making sure that the final states are not accessible. But how can a state not be accessible if a DFA has all of its transitions defined?

$\endgroup$
3
$\begingroup$

Consider a 2-state DFA over the alphabet $\{a\}$ (single character alphabet) that accepts only the empty string:

only empty string accepted

In this DFA, state 0 is the start state, and also the only accepting state. Now, if state 1 were the start state (but state 0 still the only accepting state), what strings would this machine accept?

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.