I ran into a problem of determining if two regular expressions would have any possible matches in common. For example:
Fo*bar and Fo+bar
- if $R_1$ and $R_2$ are two regular languages
- can one determine if $R_1 \cap R_2 = \varnothing$ ?
- And if one can what algorithms / methods can perform such a determination?
- And are these algorithms / method NP hard?