From JBRYAN@pstcc.cc.tn.us Tue Feb 20 16:06:52 1996 Return-Path: Received: from PSTCC4.PSTCC.CC.TN.US by life.ai.mit.edu (4.1/AI-4.10) for /com/archive/cube-lovers id AA02988; Tue, 20 Feb 96 16:06:52 EST Resent-From: JBRYAN@pstcc.cc.tn.us Resent-Message-Id: <9602202106.AA02988@life.ai.mit.edu> Received: from pstcc.cc.tn.us by pstcc.cc.tn.us (PMDF V5.0-3 #11457) id <01I1FXF1NAVY8X1JD9@pstcc.cc.tn.us> for cube-lovers@ai.mit.edu; Tue, 20 Feb 1996 16:05:42 -0400 (EDT) Resent-Date: Tue, 20 Feb 1996 16:05:42 -0400 (EDT) Date: Tue, 20 Feb 1996 16:05:34 -0400 (EDT) From: Jerry Bryan Subject: Re: Group/graph status? In-Reply-To: <9602132109.AA28288@poster> Sender: JBRYAN@pstcc.cc.tn.us To: Cube-Lovers Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Content-Transfer-Encoding: 7BIT On Tue, 13 Feb 1996, michael reid wrote: > jerry bryan was counting (and storing) positions close to start > on magnetic tape. he gave figures for positions within 7 face > turns on july 19, 1994 and positions within 11 quarter turns on > february 4, 1995. (jerry, how many reels of tape did this take?) It was a little better than 100 tapes. It was roughly 20GB of data. I stored 14 bytes per position (could have done it in 13 bytes, but I stored the lengths with each permutation). Each "position" was really a representative of an equivalence class of M-conjugates (usually) containing 48 elements. Hence, it took about 14/48 bytes (about 2.33 bits) to store each position. This isn't too shabby, but it is nowhere as compact as the coding scheme discussed in the "How Big is Big?" thread. > > the diameter isn't known. the best lower bounds are 20 face turns, > or 24 quarter turns, both from considering the position "superflip". > the best upper bounds are 29 face turns, or 42 quarter turns. A 24q process is known for superflip. It is known that superflip is greater than 19f. Is a 20f process known for superflip? = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Robert G. Bryan (Jerry Bryan) jbryan@pstcc.cc.tn.us Pellissippi State (423) 539-7127 10915 Hardin Valley Road (423) 694-6435 (fax) P.O. Box 22990 Knoxville, TN 37933-0990