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Subject: Re: Chess and O(1)

Author: Dann Corbit

Date: 11:03:01 05/09/01

Go up one level in this thread


On May 09, 2001 at 13:50:33, Ricardo Gibert wrote:

>On May 09, 2001 at 13:47:32, Jeremiah Penery wrote:
>
>>A lot of people seem to be saying that chess can be solved by an O(1),
>>constant-time, algorithm.  Technically, this may be true.  _IF_ you had the
>>proper algorithm that was capable of computing chess exactly[1], it could
>>exhibit constant-time behavior.  The problems are that no such algorithm exists
>>today, and the constant would be so large as to have no relevant meaning in
>>today's world - i.e., it would likely be greater than the age of the universe.
>>All chess programs are currently using some sort of tree-searching algorithm
>>(Alpha-Beta or variant), which are provably O(exp(n)) algorithms.  Time
>>increases exponentially with the increase in input depth - depth 5 takes
>>exponentially less time than depth 6, which in turn takes exponentially less
>>time than depth 7, and so on.  The fact that depth _eventually_ ends _IN CHESS_,
>>has nothing to do with the complexity of the algorithm.  Theoretically you can
>>give the same algorithm an infinitely sized tree, so that constant-time solution
>>is impossible.  For those who say that chess is O(1), it can't be so if the
>>program in question is using a tree-search algorithm!
>>
>>
>>[1] This O(1) chess algorithm would have to solve the game not by computing a
>>tree, because tree-search is demonstrably O(exp(n)) for this type of tree.
>
>That it is a tree is not relevant. The tree is finite. That's enough.

So your requirement is that the tree is infinite?

As popeye the sailor says:
"Uck, uck uck, uck."



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