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Subject: Re: a mate to solve (GLC2.15c -- 5 minutes)

Author: Tim Foden

Date: 13:03:13 10/10/01

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On October 10, 2001 at 15:31:17, Dann Corbit wrote:

>On October 10, 2001 at 09:23:21, Tim Foden wrote:
>
>>Green Light Chess (96MB Hash, 920MHz Duron, no tablebases) claims that Rg3 is a
>>mate in 11 after 2 mins 30 secs, and that it is a mate in 10 after 4 mins 59
>>secs.  Finally it finds a different line for mate in 10 after 7 mins 56 secs.
>>
>> 14   2:30 +Mate11 118131k  Rg3 2. Kc5 h3 3. b8=Q Rxb8 4. Rd1 g1=Q+ 5. Rxg1
>>                              Rxg1 6. Kd4 h2 7. Kc4 h1=Q 8. Kd4 Rd1+ 9. Ke3
>>                              Re8+ 10. Kf2 Rd2+ 11. Kg3 Rg8#
>> 15   4:59 +Mate10 236044k  Rg3 2. b8=Q Rxb8 3. Kc5 h3 4. Kd6 h2 5. Ra1 g1=Q 6.
>>                              Ra5+ Kf6 7. Ra6 Rb6+ 8. Kc7 Rxa6 9. Kd7 Rg7+ 10.
>>                              Kd8 Ra8#
>>Cheers, Tim.
>>
>
>That's a truly astonishing result!  Finding the closest mate faster than a
>dedicated mate solver.

I don't really think it is so astonishing Dann.  Chest is *proving* that a
mate-in-10 is the shortest that is possible.  Green Light is not.  It wouldn't
be sure until at least 21 ply (and perhaps deeper).  It's those damned
extensions a that allow normal game playing programs to find these mates :)

Now... if we had a mate that didn't trigger so many extensions then I'm sure
chest would find it first.

Cheers, Tim.

>It seems if GLC can work itself into an advantageous
>position, it can really exploit it.



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