I have read that minimizing regular expressions is, in general, PSPACE-complete. Is it known whether minimizing regular expressions without the Kleene closure (star, asterisk) is in P?
The language of any such regular expression would be guaranteed to be finite. I suppose an equivalent question is whether the problem of constructing a minimal regular expression from a known finite language is any easier than minimizing an arbitrary regular expression. It seems like this should be the case.