Author: Albert Silver
Date: 06:32:43 01/26/02
Go up one level in this thread
On January 26, 2002 at 09:27:03, Sune Fischer wrote:
>On January 26, 2002 at 09:07:51, Albert Silver wrote:
>
>>>>>Realisticly a 2800 player probably has a branchfactor of no more than 2, ie. he
>>>>>is able to always choose the best or second best move (on average).
>>>>>If the average game lasts 100 moves, then that is still 10^30 plausible games of
>>>>>which only a handfull will be good enough against *perfect* play.
>>>>>Poor odds I agree with you :)
>>>>
>>>>You're presuming that anything other than one move, the best move, will lose
>>>>forcibly to best play. I believe that more than one move is available to a
>>>>non-loss thus perfect play would be often a flip of the coin between a few
>>>>(perhaps three as I hypothesized in another post in the thread) moves. I have
>>>>seen no evidence to suggest there is only one path to a non-loss and that a
>>>>single path of perfect play is needed to avoid it. Everything we know whether
>>>>from personal research or from the current tablebases suggests there are several
>>>>paths. If this were accepted to be true, the question would be whether the 2800
>>>>player is incapable of hitting on _one_ of these non-losing moves (according to
>>>>perfect play).
>>>>
>>>> Albert
>>>
>>>You could interpet in an similar way; there is a 50% chance of the 2800 chooses
>>>a move that is *good enough*.
>>>It was just an estimate, probably way off :)
>>>
>>>Suppose that a *correct* move is done with 95% certainty (on average) and that
>>>the average game length is only 60 moves, then he has a 0.95^60 = 4.6% chance of
>>>a draw!
>>>
>>>This is perhaps more realistic?
>>>
>>>-S.
>>
>>Well, a few things come to mind. One is that there would be more than one
>>correct move to hit on.
>
>Yes, and that why I rephrased it to be a *correct* move rather than *the best*
>move, by *correct* I mean a move that isn't losing.
>
>
>>Second that I wasn't aware that his chances changed with
>>each move, so I don't think that the longer the game the worse his chances. Give
>>a 2800 player a dead equal dry game and I don't think he will suddenly be in
>>danger of losing just because it can take 40 moves to trade off the pieces and
>>pawns and play the endgame to the end. There is more to chess than probability.
>>
>> Albert
>
>What I meant was, that at every move he has a 5% chance of _not choosing the
>correct move_, ie. he "blunders" by playing inaccurate.
>That is an average percentile taken out of the blue of cause, but the tablebase
>test could give us a hint whether we are talking 95% or 50%, it would allow us
>to calculate the rating of a perfect player, which was the goal I believe.
>
>-S.
I was addressing two things: Dann's statement that against perfect play,
Kasparov (or any other 2800 player) would lose 1000 games in 1000. And your
statement that against perfect play in a game of say 60 moves he only had a 4.6%
chance of surviving. I think both statements are completely unreal and show
little understanding of certain realities of both chess and their ability. You
could also take a dead equal rook endgame where there is no chance for the
mighty player to calculate a line to the very end and I would still adamantly
state that his chances of losing are _zero_ and not some percentage that grows
exponentially with each move played.
Albert
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