From Edwin Clark, 20 Nov 2002:
Speaking of reviews of ANKOS. Here's a review by Lawrence Gray that is somewhat more substantial than Kranz's review:
www.math.umn.edu/~gray/pdf/wolfram.pdf ...
Well worth reading; he was apparently present at the 1998 Santa Fe meeting. Having hinted at the legal wrangle, let us hope that he is correct in saying that Cook's paper may finally be released. The proceedings have kept being put off and off (latest estimate January 2003); dare one hope to see it there? Melanie Mitchell has an extremely perceptive review of ANKOS in Science, which had not yet arrived in Puebla at the time of my last posting (but by now E.C. has included it in his list).
And by the way, does anyone know if Mathew Cook's proof of the universality of CA 110 (as presented in ANKOS) has been verified by workers in the area?
Some progress has been reported in this area; see my previous postings or the postings in the ``cellular automata'' usenet group. The necessary collisions are spectacular and were easy to verify, given that we had already done considerable work in this area. Global synchronization is harder to check because it takes place over such a wide area and long time span. Apparently there is nothing better to do than to sit in front of a screen and watch it, although segments can always be captured and printed. What at first seemed to be an error or a mislabelling turns out to be due to the sketchy nature of the information presented in the book. More aspects of the collisions have to be taken into account than are shown in the figures. Inviting people to run the Mathematica programs associated with the book does not lead to independent confirmation of the assertions in the text. Using a proprietary language which can only be run in a proprietary operating system does not necessarily imply falsification of the results (but look at what that boy Schoen just did at Bell Labs). We have just had some discussion here on math-fun of the acceptability of the Four Color Theorem, wherein be it noted that running an independently written program on a different model of computer was considered to be reassuring. What is for sure is that the pictures in the book were carefully selected and hopefully no mistakes were made in transcribing their code into the manuscript. Handsome indeed are the results. But lacking even an attempt to explain the programs, how would one go about trying experiments of one's own? Such as bombarding the data with a string of nulls, or trying to merely copy or complement an incoming data stream? Or writing that binary counter? Supposing that all the adjustments which are inherent in the collision parameters can successfully be made (and bear in mind that the scheme outlined in ANKOS practically forces the use of a cyclic system), the larger question arises as to whether there is a Turing Machine lurking in the background somewhere. We are offered Kolakoski's automatic substitution systems, and we can search the literature of small Turing Machines. There isn't much to work with here in Puebla except the Internet, but we haven't been able to find any paper giving an explicit connection. Maybe soomeone can offer some references? - hvm