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Subject: Re: Maybe a mate?

Author: Heiner Marxen

Date: 14:17:35 12/30/02

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On December 30, 2002 at 15:41:49, Dieter Buerssner wrote:

>On December 30, 2002 at 15:08:22, Heiner Marxen wrote:
>
>>>>>>>>>b2r2kr/p1pqb1p1/1p5p/4p3/2P1N1P1/1P2Q3/P3P2P/4KRR1 b - - 0 1
>
>>>>>>>Perhaps Chest can prove a mate after
>>>>>>>
>>>>>>>1...Bh4+  2. Rg3 Qd1+ 3. Kf2 Rf8+ 4. Qf3 Qd4+ 5. Kg2
>>>>>>>
>>>>>>>(After 5. Ke1 it is mate in 10 or faster, so this should also be possible?)
>>Your analysis matches the output of Chest.  Here is its PV
>>
>>PV: Bxe4 c5 h5 h3 Bxf3+ Rfxf3 Bxg3 Rxf8+ Kxf8 Kxg3 Qf4+ Kg2 hxg4 h4 Rxh4 e3 Rh2+
>>Kg1 Qf2#
>>
>>In the refutation table we have:
>
>Which I don't understand, yet - but I will read it up ...

It is kind of a 2-ply deep tree that Chest explored, and what it found
about the resulting positions:

>>refu 19: Bxe4    c5      [   8-]
>>solu          1: Qxe4    [   7+]
                               ^^---- success for subjob
                               +----- depth of subtree analysis
Spelled out:
There is a refutation after Bxe4, namely c5, after which there is no mate-in-8.
But there is also a solution, when Bxe4 is followed by Qxe4, then there does
exist a mate-in-7.  etc

Cheers,
Heiner



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