Given an e-NFA. It is easy to find a string that is accepted by it. But, how do we find if the given e-NFA accepts "All" the strings over the alphabet. Or if there is a string that is not accepted by it.
Of course the usual way is to construct a DFA, or complement the e-NFA but since we are talking about the whole language, I was wondering if there is a much more efficent method in the worst case.