Why no RE match of A AND B?

[Anders J. Munch]

"Andrew Koenig" <ark at research.att.com> wrote:
> jcm> I believe you're incorrect about this.  Regular languages are closed
> jcm> over intersection.
> 
> I guess you're right -- you can always make a DFA with states that
> consist of the cartesian product of the states of the operand machines.
> But implementing it efficiently may be another matter.

Have done it, it's easy at the DFA level.

- Anders