which would produce the desired group.
I have no idea why things are not so simple, and what gap means by "value".
It must be a simple thing, and I would greatly appreciate any help on this
(the best help would be an exact example that worked - I thought I did exactly
what the book said, but it seems that I wasn't doing that).
Thanks, Victor Pambuccian
P.S. It is true that I was all the time in gap> so maybe the program didn't know I
meant to do this in grape? Do I need to "call" grape?