2013-03-14 added a stimes_ac lemma for Xingyuan
Christian Urban <christian dot urban at kcl dot ac dot uk> [Thu, 14 Mar 2013 18:02:26 +0000] rev 223
added a stimes_ac lemma for Xingyuan
(0) -100 -30 -10 -1 +1 +10 +30 tip