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Subject: Maybe this one then ?

Author: Michael Diosi

Date: 06:52:53 01/30/06

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On January 30, 2006 at 09:35:38, Uri Blass wrote:

>On January 30, 2006 at 09:08:09, Michael Diosi wrote:
>
>>On January 30, 2006 at 08:58:24, Uri Blass wrote:
>>
>>>On January 30, 2006 at 08:51:12, Uri Blass wrote:
>>>
>>>>On January 30, 2006 at 08:40:09, Uri Blass wrote:
>>>>
>>>>>On January 30, 2006 at 07:49:53, Michael Diosi wrote:
>>>>>
>>>>>>
>>>>>>Hello.
>>>>>>
>>>>>>I have a few, this one is from Russel/ Norvig : Advances in Artificial
>>>>>>Intelligence A Modern Approach (page 130)
>>>>>>[d]8/1p1P4/k1p5/8/8/3PPPPP/r7/7K b - - 0 1
>>>>>>
>>>>>>You can see here that black can give a series of checks "pushing" the inevitable
>>>>>>queening over the horizon. So programs how don't see it will have a positive
>>>>>>score for black.
>>>>>>
>>>>>>
>>>>>>I can look for more if you want.
>>>>>>
>>>>>>MD
>>>>>
>>>>>This is a bad example
>>>>>
>>>>>Amir Ban is correct.
>>>>>
>>>>>The horizon effect is effect that cause the program to play worse move because
>>>>>it does not see deep enough.
>>>>>
>>>>>This example is not the horizon effect but only not seeing deep enough.
>>>>>
>>>>>Uri
>>>>
>>>>Note that not every case that the program play worse move because of not seeing
>>>>deep enough means the horizon effect.
>>>>
>>>>The idea is that the program has some illusion that it can prevent some problem
>>>>but only cause itself a bigger problem because it delay the problem to position
>>>>that it does not see.
>>>>
>>>>In the example the program has an illusion that it can prevent the pawn from
>>>>promotion but it does not cause it to do mistakes and sacrifice material so I do
>>>>not think that it is good example.
>>>>
>>>>Without check extensions if the program sacrifice the rook then it can be a good
>>>>example.
>>>>
>>>>Uri
>>>
>>>The following sentence from the article summerize it:
>>>
>>>"The horizon effect is said to occur when
>>>the delaying moves unnecessarily
>>>weaken the position or give up additional material
>>>to pospone the evantual loss"
>>>
>>>Uri
>>
>>Hi,
>>
>>This is exactly what its happenening. It is delaying moves unnecessarily giving
>>checks and in the end material (the rook). The pawn promoting move is beyond the
>>horizon of the program (not really in this case). In other words the program
>>can't see that white will promote anyway. Each black move brings white closer to
>>promotion and to the horizon.
>>
>>
>>
>>MD
>
>The delaying checks in your example do not weaken the position and there is
>simply no better choice.
>
>Uri

Hi,

Hmm I still think it was a good example but how about this one then:

[d]8/6k1/6p1/5p2/1p2p3/1P6/b1PK3R/8 w - - 0 1

http://www.ics.uci.edu/~eppstein/180a/990204.html

MD



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