[pcre-dev] Comparing Regular Expressions

I am new to PCRE, and I am looking at incorporating regular expressions into
a new product.

I need to know whether either of the following capabilities are available,
either in PCRE, or in an add-on package -

.         Given two (2) regular expressions, does one regular expression
superset all possible pattern matches of the other regular expression?

.         Given two (2) regular expressions, does there exist any union of
potential pattern matches?

John P. Baker