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Subject: Re: What is a combination? Define it please!

Author: Robert Henry Durrett

Date: 11:55:16 09/06/98

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On September 06, 1998 at 14:27:08, Don Dailey wrote:

>>>Shall we try it on the group?   What is a combination?  Give an answer
>>>that has no ambiguity whatsoever.   I have never seen one in any book,
>>>but I've seen many attempts.  You may be able to come up with a strict
>>>definition of what a combination is, but I'll be many will disagree
>>>about what this definition should be.   Your definition will probably
>>>not match peoples perception of what they think a combination is.
>>
>>>- Don
>>
>>
>>   An interesting game. I tried to give an objective definition of a
>>combination. at first sight it seemed easier than it was in reality! Here is my
>>attempt :
>>
>>
>>Combination : A series of 2 or more consecutive moves involving the sacrifice or
>>investment of material, and by which the player that initiated it gains some
>>sensible benefits whatever his/her opponent play to counter it. The benefits
>>could be a greater material win in the end or in another form (e.g. a huge space
>>advantage, a strong passed pawn etc.).
>>
>>
>>
>>   Having said that, I will now give (I did not look at it before writing mine)
>>the one of IM Nicolas Giffard in his book "Le guide des echecs" (that could be
>>translated as "The Guide of Chess". The translation is from me :
>>
>>
>>Combination: A series of moves from one side provoking forced or almost forced
>>replies, allowing to achieve a concrete goal. A combination correctly realized,
>>this way, could bring a small advantage or as well the checkmate of the
>>opponent.
>>
>>Serge Desmarais
>
>
>Nice try, but not good enough!  Not to worry, I don't think I can do
>much better.
>
>The Serge Desmariais definition is more ambiguous than yours!  He
>did not even define what a concrete goal is.  I suppose it does
>not matter, it's only important that your combination achieves
>whatever you define to be your own personal concrete goal.
>
>Your definition does not tell me anything about when the huge win
>or advantage was achieved.  Do you determine this by doing a
>quies search and trusting the results?   You have to use a lot
>of human judgement to determine if your move sequence fits the
>definition.  In other words it will be possible in principle to
>contruct borderline cases where experts will disagree.
>
>The definition must be completely free of any ambiguious terminology.
>100/100 people should be able to apply your defintion to any
>sequence of moves and determine exactly where a combination starts
>and stops.
>
>- Don

If you want to be completely rigorous about this you must treat this the same
way a mathematician develops a theory, such as boolian algegra.  In every case,
the theory is founded on unproven axioms.  Then there is a bunch of definitions
and theorems, connected by proofs.  The steps in the proofs must be generally
accepted as being valid, but the validity of the steps in logic cannot be proven
and are like the unproven axioms which form the foundation of any mathematical
theory.

Note that definitions are never proven!  They are selected by those who are
developing the theory.  If the theory is being developed by a group of people,
as the case here, then everybody must agree on the ACCEPTABILITY of the
definitions, but not on the "truth or falseness" of the definitions.  There is
no such thing as a "true" definition or a "false" definition.  But there sure
can be "ambiguous" definitions.  These ambiguities become apparent whenever a
proof is attempted in which the assertion to be proven uses the defined term as
part of the definition.

I suggest that some "reasonable-sounding" definitions be selected and see where
they lead.  If a term later proves to be poorly defined, there is always the
opportunity to change the definition.

But this is the BIG question:  Do you guys really want to go through all of
this?



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