Fri, 08 Jan 2010 10:08:01 +0100 Proved concat_empty.
Cezary Kaliszyk <kaliszyk@in.tum.de> [Fri, 08 Jan 2010 10:08:01 +0100] rev 824
Proved concat_empty.
(0) -300 -100 -30 -10 -1 +1 +10 +30 +100 +300 +1000 tip