Thu, 08 Jan 2009 10:43:09 -0800 add lemma dvd_diff to class comm_ring_1
huffman [Thu, 08 Jan 2009 10:43:09 -0800] rev 29409
add lemma dvd_diff to class comm_ring_1
(0) -10000 -3000 -1000 -300 -100 -30 -10 -1 +1 +10 +30 +100 +300 +1000 +3000 +10000 +30000 tip