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Subject: Re: The depth of the chess tree, the size of the game of chess...

Author: Angrim

Date: 12:49:19 05/11/01

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On May 11, 2001 at 03:29:43, Dann Corbit wrote:

>On May 11, 2001 at 01:49:03, Angrim wrote:
<snip>
>>If your goal is to determine how hard it is to solve chess, then yes.
>>Rather then go into a lengthy rant here, let me give an example.
>>The following position has pawns advanced a total of 4 squares, so
>>subtract 4*50 from the max depth, and your math suggests that there are
>>38^(5900 -200) total games of chess that can result from this position.
>>However, the position is trivial. No need for sqrt(38^(5900 -200))
>>positions to be searched or stored...
>>
>>[D]rnbqkbnr/pppp1ppp/4p3/8/6P1/5P2/PPPPP2P/RNBQKBNR b KQkq g3 0 2
>
>Yet there are many quintillions of quintillions of qintillions of games that can
>sprout from here.
>
My point being that if your goal is to solve this position, then all
but 1 of those games is totally irrelevant.

>Unless we assume optimal play.
We only need to assume optimal play for one side, unless chess turns out
to be a draw.  I'm not actually good enough at chess to determine whether
or not the game is a theory draw :-) .

>Positions like this one are intensely interesting, however.  We could formally
>trim all forward branches from here. Unless I am missing something.
>
>Which brings up another thought.  What percentage of moves are so horrible that
>they are not even worth considering.  Is it 99.99999999999999999999999999%?

not of moves, but of the set of all possible games, the percentage that contain
an error of that magnitude is roughly 99.999<insert 2 pages of 9s>99%
Even if you define such an error as "any move which can be shown to lose
with a 1 second search" rather than the possibly unsound "any move which
crafty would score as 10 points lower than the favorite after a 1 second
search".

Angrim
ps. so much for my attempt to avoid a lengthy rant.  But at least I
left out the 2 pages of 9s ;)



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