"prepare_proof" has been simplified because
rewrite_rule and rewrite_goals_rule check for empty lists.
The list of premises is *not* passed to Thm.compress; this was tried, but
the potential storage gains seemed not to justify the cpu time required.
$Id$
This directory contains some axiomatic type class demos.
Tutorial/ Some simple axclass demos that go along with the paper
"Using Axiomatic Type Classes in Isabelle --- a
tutorial".
Group/ Basic group theory with axiomatic type classes.