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Subject: Re: How many programs can see the draw in the 2nd game of DB vs Kasparov?

Author: Robert Hyatt

Date: 07:24:22 02/28/01

Go up one level in this thread


On February 27, 2001 at 10:49:29, Uri Blass wrote:

>On February 27, 2001 at 10:07:31, Robert Hyatt wrote:
>
>>On February 27, 2001 at 08:24:14, Jorge Pichard wrote:
>>
>>>I believe that the drawish move was Qe3! instead of the Qxc6?  Can somebody
>>>post the FEN string that produce the graphical position for me. Plus I wonder
>>>what program save the draw in the shortest time possible?
>>
>>
>>None can see this.  It is a 60+ ply repetition.  Way beyond anything we can
>>see today.
>
>We need to test all the programs in order to say that none can see it.
>
>Some programs like dark thought are not available so we cannot know that none
>can see it.
>
>The fact that it is 60 ply repetition is not a proof that none can see it
>because programs only to need the right extensions to see the relevant 60 plies
>forward.
>
>If you are wrong then testing only one program is enough to prove it.
>
>Uri


Here I disagree.  I fully understand what chess programs are doing in the
tree, and I have a good grasp of the exponential search issue.  While what
you say is _possible_, it may also be possible to exceed the speed of light
in space travel one day.  But _not_ with today's technology.  Same for the
search issue.  To reach 60+ plies in that position would require some
impossibly accurate extensions... because if they are triggered in the _wrong_
positions, the tree will explode to an impossible-to-search size.  If a chess
program could search this position with an effective branching factor of 2,
it would still have to overcome the issue of 2^60 to get deep enough to find
that draw.

It would be more likely to recognize potential perps by static analysis, because
the actual tree here is simply _impossibly_ big.  Humans don't solve it by
searching until they _see_ the repetition... they solve it by searching until
they reach a position where they recognize that a repetition is unavoidable.
Programs don't yet work like that.  I am not sure they will for a _long_ time.



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