Some regular expressions are ambiguous. Some are not.
a*b* is unambiguous for example. Expression
a*a* is ambiguous but it can be written in the unambiguous form 'a*`. The answer to this question gives an algorithm for deciding whether a regular expression is ambiguous.
- Is there an algorithm for finding an equivalent unambiguous form of any given RE?
- Are there REs that are inherently ambiguous?
(This question seems relevant by title; not by content)