From dik@cwi.nl Sat May 30 18:12:35 1992 Return-Path: Received: from charon.cwi.nl by life.ai.mit.edu (4.1/AI-4.10) id AA10599; Sat, 30 May 92 18:12:35 EDT Received: from boring.cwi.nl by charon.cwi.nl with SMTP id AA26864 (5.65b/2.10/CWI-Amsterdam); Sun, 31 May 1992 00:12:31 +0200 Received: by boring.cwi.nl id AA02915 (5.65b/2.10/CWI-Amsterdam); Sun, 31 May 1992 00:12:30 +0200 Date: Sun, 31 May 1992 00:12:30 +0200 From: Dik.Winter@cwi.nl Message-Id: <9205302212.AA02915.dik@boring.cwi.nl> To: J.M.Kloosterman@research.ptt.nl Subject: Re: Lower-bound Kociemba's algorithm Cc: cube-lovers@life.ai.mit.edu > I have done an exhaustive search and none of the 6 situations of 18 moves > could be reduced to 17 moves (within the group of ). > For the case you want to verify, one of them is: > > L2 U R2 B2 U2 B2 L2 D2 L2 F2 D' L2 B2 F2 L2 F2 U' D > Of course I verified it ;-). This one does indeed kill Kociemba's algorithm. On a fast processor (65 MHz SPARC) with a larger limit database than Kociemba is using himself (the database is about 5 MByte for the second phase), it took 3 hours 15 minutes to find a minimal solution. Of 18 moves.