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Subject: Re: Verified Null-Move Pruning, ICGA 25(3)

Author: Uri Blass

Date: 11:32:40 11/20/02

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On November 20, 2002 at 11:43:10, Omid David Tabibi wrote:

>
>            ICGA Journal, Vol. 25, No. 3, pp. 153-161, September 2003
>
>
>                          Verified Null-Move Pruning
>
>                    Omid David Tabibi and Nathan S. Netanyahu
>
>
>                                   Abstract
>
>In this article we review standard null-move pruning and introduce our extended
>version of it, which we call verified null-move pruning. In verified null-move
>pruning, whenever the shallow null-move search indicates a fail-high, instead of
>cutting off the search from the current node, the search is continued with
>reduced depth.
>
>Our experiments with verified null-move pruning show that on average, it
>constructs a smaller search tree with greater tactical strength in comparison to
>standard null-move pruning. Moreover, unlike standard null-move pruning, which
>fails badly in zugzwang positions, verified null-move pruning manages to detect
>most zugzwangs and in such cases conducts a re-search to obtain the correct
>result. In addition, verified null-move pruning is very easy to implement, and
>any standard null-move pruning program can use verified null-move pruning by
>modifying only a few lines of code.

Some comments:

1)If I understand correctly your idea let the computer to find every idea that
is based on one zugzwang after enough time but not ideas that are based on more
than one zugzwang.

Am I right?

2)I guess that it is not good news for Amir Ban because it seems that most of
the null move pruning programs like Fritz are going to earn rating when Junior
cannot because it does not use null move prunning.

Uri



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