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Subject: Re: Congratulations to Rebel Century

Author: blass uri

Date: 08:15:35 10/05/99

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On October 05, 1999 at 10:23:46, Lanny DiBartolomeo wrote:

>On October 03, 1999 at 23:44:31, Robert Hyatt wrote:
>
>>On October 03, 1999 at 23:17:29, Ricardo Gibert wrote:
>>
>>>[snip]
>>>>
>>>>my webster's defines 'sacrifice' as 'voluntarily giving up something of
>>>>value'.  I have a hard time saying 'I will sacrifice a ten-dollar bill if
>>>>you will give me a 20 dollar bill in return...'
>>>>
>>>>:)
>>>
>>>Ok, you got me. I neglected to explicitly state I was refering to the _chess_
>>>version of the term.
>>>
>>
>>
>>then here is a 3-move sequence. Sacrifice or combination?
>>
>>RxB, NxR, RxN.
>>
>>RxB obviously dumps a rook for a knight.  or if you look to the end of the
>>combination it wins two pieces for a rook which is a significant advantage.
>>
>>Sacrifice or combination?
>>
>>How is that different from QxP+, RxQ, RxR#??
>>
>>Dumping a queen for a pawn?  Or winning the king?
>>
>>
>>>>
>>>>But I don't object to the term being used..  I just think that for a computer,
>>>>the concept 'sacrifice' is wrong.  It is just a perfectly computable
>>>>combinational tree search...
>>>
>>>You can give up a bishop to obtain a draw by perpetual check and because you
>>>never get the material back, it is a called a sacrifice. I know it seems trivial
>>>and is not what people generally have in mind when they use the term
>>>"sacrifice", but I do believe it's use in such cases is fairly universal.
>>
>>
>>in the case of a computer, it isn't 'sacrificing'.  It _sees_ that it can
>>draw or that it can win.  IE it isn't giving up _anything_.  A human might
>>toss a bishop 'thinking' (but not sure) than he can force a perpetual.  But
>>a computer either 'proves' that it can force it, or it won't ever go for the
>>move in the first place.  IE we (as humans) gamble on things all the time.  But
>>would it be the same as saying "I'll flip a coin and if it is heads I win, and
>>if it is tails you win" if I rig the coin so there is _no doubt_ that it will
>>end up heads when I want?
>>
>>That is the minor point here...  computers don't sacrifice in the traditional
>>way usually.  There are exceptions like the famous chaos sacrifice vs chess
>>4.x where chaos didn't see any materian coming back, but thought the position
>>justified the Nxe6 sac anyway...  I see a number of those in Crafty.  More than
>>I really want to see.  But they do come close to the definition of a sacrifice
>>as nothing "real" is won back, just some intangible positional things that may
>>well not be enough to win with.
>
>Yes,even then, did chaos choose the move against a better move as related to its
> score,if it saw a move that left its score at +1.00 or the move it made at
>  -1.00 did it go for the -1.00? I think a real sac in a computer is if it
>chosses a move against its score, or else it is still going on raw calculation.

A serious human does not do sacrifices by your definition.
Sacrifice is the same as something that you believe that is clearly wrong by
your definition.

Uri



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