Fri, 21 Jan 2011 22:23:44 +0100 Christian Urban separated type preservation and progress into a separate file
Fri, 21 Jan 2011 22:02:34 +0100 Christian Urban substitution lemma in separate file
(0) -1000 -300 -100 -30 -10 -2 +2 +10 +30 +100 +300 tip