Optimal beta-reduction: lecture 2

This past Tuesday (June 19) I gave the second lecture in the series I am working on, about optimal beta-reduction.  The screencast can be found here.  This lecture covers the basic nondeterministic graph reduction rules for lazy duplication.  The notes you will see my writing are here in ora and jpeg formats.  The lambdascope implementation I try using (and many thanks to Jan Rochel for this!) can be found here on hackage.  The lambdascope paper can be found here.