Author: Amir Ban
Date: 03:55:26 11/26/98
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On November 26, 1998 at 05:07:05, Bruce Moreland wrote: > >On November 26, 1998 at 04:41:15, Graham Laight wrote: > > >>Given this claim that a big new discovery has taken place, may we just recap >>what we're discussing here, please? >> >>Correct me if I'm wrong (I probably am, because I haven't been following the >>thread in detail), but my understanding is as follows: >> >>In DB V GK 97 game 2, DB played 36. axb5. >> >>This is a move one would not expect a computer to play, because it misses an >>opportunity to win material with 36. Qb6, which is what one would expect a chess >>computer to do. >> >>Those who believe that DB found the move for itself, without help, have, in >>support of their case, stated that DB would have been able to see that 36. Qb6 >>leads to a forced draw. >> >>To discover if this is true, Bruce Moreland has asked that as many people as >>possible should run the position for as long as possible on their own computers, >>to see whether, at some depth of search, the eval for 36. axb5 jumps ahead of >>the eval for 36. Qb6. > >I'm hoping that someone will get lucky with a search extension or whatever, and >that this will more or less prove that it is possible to understand Qb6 in >finite time. > >Best would be another program that played axb5. > >Second best would be that something gets a score drop such that the value of the >position is < +1.00. > >We can argue about what this means, if it happens. But I don't think it is >going to happen. I think everyone is going to get Qb6 +1.X. > >>In doing this, Ernst Heinz has discovered that, at ply 21, a line of >>continuation that includes move 40. Ra6, appears to push the draw too far into >>the distance for any computer to have a realistic chance of seeing it. >> >>This adds to the case that 36. axb5 is not a move one would expect a computer to >>make, and therefore supports Gary Kasparov's view that the move requires further >>explanation from IBM. >> >>Right or wrong? > I reposted the "draw" analysis here in another thread. I think this discovery is not important for the argument, because the draw was anyway much too far for DB to see. >No. I was somewhat concerned that if this search failed, people would assume >that IBM is cheating, but this doesn't follow. If I go looking for something >and I find it, that is a good indication that the thing exists. But if I don't >find it, it doesn't prove that the thing doesn't exist. > >So I think that we are back to square one, although we've shown that an obvious >brute force attempt to disprove the cheating notion fails. > >My personal opinion is that DB figured this position out better than the rest of >us have. I have no evidence that supports this. I don't think there is any >evidence for cheating, either. > >bruce This is not all the evidence. The full case is this: 1. The basis for preferring axb5 over Qb6 remains unknown. 2. axb5 was adopted in unexplained circumstances: it never showed up in the normal search but only came up in a main line reconstruction after the search was interrupted while Qb6 was the best move. 3. IBM will not disclose any information or talk about this. Amir
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