From dik@cwi.nl Tue Aug 24 20:43:14 1993 Return-Path: Received: from charon.cwi.nl by life.ai.mit.edu (4.1/AI-4.10) for /com/archive/cube-lovers id AA05145; Tue, 24 Aug 93 20:43:14 EDT Received: from boring.cwi.nl by charon.cwi.nl with SMTP id AA02014 (5.65b/3.10/CWI-Amsterdam); Wed, 25 Aug 1993 02:43:01 +0200 Received: by boring.cwi.nl id AA11725 (4.1/2.10/CWI-Amsterdam); Wed, 25 Aug 93 02:42:58 +0200 Date: Wed, 25 Aug 93 02:42:58 +0200 From: Dik.Winter@cwi.nl Message-Id: <9308250042.AA11725.dik@boring.cwi.nl> To: cube-lovers@life.ai.mit.edu, reid@math.berkeley.edu Subject: Re: Diameter of cube group? > > Continuing and waiting for a config that requires 21 turns, dik > here's a pattern to try: > first do 6 checkerboards of order 2 (F2 B2 R2 L2 U2 D2) and then do > superfliptwist. in other words, the group product of these two elements. As they commute I did it the other way around. But I am highly suspicious that you tried it yourself. 10 minutes and only down to 22 turns. But continuing, possibly for weeks/months. On another machine I am trying to prove that 20 is minimal for superfliptwist. 90 hours gone, still nothing. Most of the time is not spend with phase 1 set to 16 turns. Phase 1 to 13 got it doen to 20. Nothing new with phase 1 to 14 or 15. 16 turns in phase 1 allows at most 3 turns in phase 2. The latter can be time consuming. I do not know in how many cases actually something is done in phase 2. When I get to 17 turns in phase 1, I suspect in most cases in phase 2 it is immediately clear that it can not be solved. But I am patient. dik