<p>Here's another FSA to consider:</p>
<div>
<img alt="FSA with missing transitions" class="" src="{% static 'finite-state-automata-no-trap-example.png' %}" title="hover text is me" />
</div>
<p>It's fairly clear what it will accept: strings like "ab", "abab", "abababababab", and, of course {math}\epsilon{math end}.
But there are some missing transitions: if you are in state 1 and get a "b" there's nowhere to go.
If an input cannot be accepted, it will be rejected, as in this case. We could have put in a trap state to make this clear:</p>
<div>
<img alt="FSA with missing transitions" class="" src="{% static 'finite-state-automata-trap-added-example.png' %}" title="also some hover text" />
</div>
<p>But things can get out of hand. What if there are more letters in the alphabet? We'd need something like this:</p>
