From cube-lovers-errors@mc.lcs.mit.edu Fri Dec 4 13:17:06 1998 Return-Path: Received: from sun28.aic.nrl.navy.mil (sun28.aic.nrl.navy.mil [132.250.84.38]) by mc.lcs.mit.edu (8.9.1a/8.9.1-mod) with SMTP id NAA05373 for ; Fri, 4 Dec 1998 13:17:05 -0500 (EST) Precedence: bulk Errors-To: cube-lovers-errors@mc.lcs.mit.edu Date: Thu, 3 Dec 1998 23:58:19 -0500 (EST) From: der Mouse Message-Id: <199812040458.XAA26116@Twig.Rodents.Montreal.QC.CA> To: Cube-Lovers@ai.mit.edu Subject: Re: (5x5x5) edge parity corrections > The parity problem is found in 5x5x5 cubes (and 4x4x4 cubes, I > understand) when two of the edges right next to the corners (which I > call "wings") are switched. Yes, it does occur equally on the 4-Cube. Though I have never seen one, I feel certain that similar parity problems will occur on all higher-order Cubes as well, though above order 5 there will be multiple distinct types of "wings", each of which will have its own comparable potential problem. Note that the problem goes away entirely if cube faces are marked such that symmetrically placed face cubies are not visually indistinguishable, because the parity problem in question always occurs in conjunction with a similar parity problem on face cubies, but the latter is invisible on most cubes. > [...] half the time two wings need to be switched. > How do other people fix this problem? Most briefly, how I do it is to make a single quarter-turn of a slice containing one of the wing pieces involved, then fix up the damage by moving wings back into place using commutators rather than slice moves. der Mouse mouse@rodents.montreal.qc.ca 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B