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Terry McCracken
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Post subject: Re: Is this positions drawn ??    Posted: Tue May 22, 2007 4:29 am

smirobth wrote:
Dann Corbit wrote:
Terry McCracken wrote:
Uri Blass wrote:
Terry McCracken wrote:
 Uri Blass wrote: I agree that this is more convincing and can be used for what I consider as a real proof that I am lazy to construct(I still do not consider it as a proof inspite of the fact that it convinced me). I think that black even does not need the quare a6 and can do fine even on 7*7 board with only c6 and b6 In order to construct a proof that I am too lazy to do we pracitcally need simply to divide the possible pair of squares of white king and white queen to 12 classes and give the corresponding squares of black king and rook in every class. After this we need to prove that after white does a move in one of the classes black can capture the queen or make a move that goes to one of the classes. Uri

Huh??

Robin gave proof, and it's quite simple

Page One.... http://www.talkchess.com/forum/viewtopic.php?t=13872&start=0

Robin's post is convincing but I do not consider it as a proof.
I simply disagree with you about the meaning of the word proof.

Robin gave a strategy to draw the game.
A proof should prove that the strategy is really possible and that white cannot do something different that I did not imagine.

I am not sure if we practically need to do what I suggested and it is only one way to prove the draw.

Thinking about again it may be more simpler to prove that the strategy that Robin suggested is possible but it needs proof.

Here is part of the proof that you need to write in order to prove it based on my standards and not only in order to convince me(I added comments to Robin comments inside the ().

2) If the king is in check, move out of check to any one of the squares h7, g8, h8(possible but need proof because the queen may control all 3 squares from g7 and if the white king is at f8 white is winning
the white king can never go to f8 but in order to prove that black draw we need to mention the possible squares of the white king and prove that white cannot escape them in every one of the cases)

3) If the rook is not on f6 move the rook to f6(possible assuming the rook is not pinned but the rook cannot be pinned when the black king is at h7 g8 h8 and the rook is at f6 f2 c6 b6 a6).

Uri

Uri, George posted a link above, the utility you need for your final proof is
Freezer.

If this can't give a proof, then you'll have to run a hundred plys full width!

In ten years that might not be a problem

Terry

It will be a proof when freezer is run against the problem and verifies the result. Until then, it is only a very good hypothesis.

Hi Dan,
Even Freezer will not generate a true proof, in the strict mathematical sense, which seems to be what you and Uri seek. This is not only because Freezer's source is not open, as Uri mentioned, but also because Freezer does not generate a full database of all possible relevant positions. In order to keep the computation size and eventual database size manageable, Freezer allows and often even requires users to define rules that will reduce the database computation to levels manageable by Freezer. In the specific position in question at least some rules are required by Freezer. Depending on what rules a user defines the _exact_ same position might result in an evaluation of "White wins", "Draw" or "Black wins", so clearly specifying these rules properly is essential. A savvy Freezer user will be good at defining rules which will result in an accurate conclusion, but this hardly constitutes a true proof in the mathematical sense, any more than my move generating algorithm did.

P.S. I ran Freezer on the position in question. The conclusion Freezer/I reached was "Draw". However I do not have a complete set of 6 man tablebases and I had to define several rules for Freezer to use in its database generation. The first of the rules I defined was "If White's queen is captured" = draw.

Robin, you improvised and even removed the Black h6 pawn and EGTBs returned a draw. What , more proof do Dan and Uri need??

http://www.shredderchess.com/online-chess/online-databases/endgame-database.html
 Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First
Subject Author Date/Time
M ANSARI Fri May 18, 2007 8:15 pm
Tobias Lagemann Fri May 18, 2007 8:53 pm
Terry McCracken Fri May 18, 2007 9:01 pm
Uri Blass Fri May 18, 2007 9:17 pm
Robin Smith Fri May 18, 2007 9:35 pm
Alex Brown Fri May 18, 2007 9:47 pm
Uri Blass Fri May 18, 2007 10:29 pm
Torstein Wed May 23, 2007 12:33 pm
Paulo Soares Fri May 18, 2007 10:18 pm
nuff Fri May 18, 2007 10:27 pm
Paulo Soares Fri May 18, 2007 10:34 pm
Uri Blass Fri May 18, 2007 10:39 pm
Terry McCracken Fri May 18, 2007 10:53 pm
Dann Corbit Sat May 19, 2007 12:27 am
Terry McCracken Sat May 19, 2007 4:57 am
Dann Corbit Sat May 19, 2007 6:13 am
Terry McCracken Sat May 19, 2007 4:14 pm
George Tsavdaris Sat May 19, 2007 4:52 pm
Terry McCracken Sat May 19, 2007 6:15 pm
George Tsavdaris Sat May 19, 2007 6:20 pm
Terry McCracken Sat May 19, 2007 7:43 pm
Uri Blass Sat May 19, 2007 6:31 pm
Terry McCracken Sat May 19, 2007 7:39 pm
Alessandro Scotti Sat May 19, 2007 9:10 pm
Terry McCracken Sun May 20, 2007 3:27 am
Dann Corbit Wed May 23, 2007 4:17 am
M ANSARI Wed May 23, 2007 6:53 am
George Tsavdaris Wed May 23, 2007 4:19 pm
Dann Corbit Wed May 23, 2007 6:19 pm
Uri Blass Fri May 18, 2007 10:36 pm
nuff Fri May 18, 2007 10:41 pm
Uri Blass Fri May 18, 2007 11:50 pm
Graham Banks Fri May 18, 2007 11:59 pm
Uri Blass Sat May 19, 2007 12:03 am
Graham Banks Sat May 19, 2007 12:13 am
Robin Smith Sat May 19, 2007 4:00 am
Uri Blass Sat May 19, 2007 6:14 am
Terry McCracken Sat May 19, 2007 4:17 pm
Uri Blass Sat May 19, 2007 5:13 pm
Terry McCracken Sat May 19, 2007 6:09 pm
Dann Corbit Mon May 21, 2007 9:51 pm
Robin Smith Tue May 22, 2007 3:15 am
Dann Corbit Tue May 22, 2007 4:02 am
Terry McCracken Tue May 22, 2007 4:20 am
Robin Smith Tue May 22, 2007 10:24 pm
Re: Is this positions drawn ?? Terry McCracken Tue May 22, 2007 4:29 am
Dann Corbit Wed May 23, 2007 11:42 pm
J. Prata Thu May 24, 2007 12:19 am
Dann Corbit Thu May 24, 2007 12:42 am
Robin Smith Thu May 24, 2007 1:20 am
Terry McCracken Thu May 24, 2007 2:29 am
Robin Smith Thu May 24, 2007 3:21 am
Terry McCracken Thu May 24, 2007 4:29 am
Uri Blass Thu May 24, 2007 7:20 am
Terry McCracken Thu May 24, 2007 2:25 am
glorfindel Fri May 25, 2007 1:38 am
Terry McCracken Fri May 25, 2007 2:11 am
glorfindel Fri May 25, 2007 3:04 pm
Terry McCracken Fri May 25, 2007 5:04 pm
Robin Smith Fri May 25, 2007 2:35 am
glorfindel Fri May 25, 2007 3:25 pm
Richard Sutherland Fri May 25, 2007 3:50 pm
Terry McCracken Fri May 25, 2007 4:09 pm
Robin Smith Fri May 25, 2007 4:50 pm
Terry McCracken Fri May 25, 2007 5:05 pm
Dann Corbit Fri May 25, 2007 2:23 am
Terry McCracken Tue May 22, 2007 4:19 am
Dann Corbit Wed May 23, 2007 10:56 pm
Paulo Soares Fri May 18, 2007 10:15 pm
Uri Blass Fri May 18, 2007 10:26 pm
Paulo Soares Fri May 18, 2007 10:58 pm
Uri Blass Sat May 19, 2007 12:01 am
Paulo Soares Sat May 19, 2007 12:24 am
Daniel Mehrmann Wed May 23, 2007 11:40 pm

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