RE: [computer-go] citation

["Mark Boon" <tesuji@xxxxxxxxx>]

In a sense both of you are right. John is right that the ladder problem is
theoretically pspace hard. When programming you can't avoid a formal
definition of ladders like John's, as a program has little use of a vague
definition of a 'ladder' as something that results in the shape of a ladder.
The shape is only the result of some practical examples of the formal
definition, not the other way around.

On the other hand, Harry is right that making a program that reads ladders
is a fairly trivial task. For practical purposes you can limit the ladder
depth (to say 70 moves, enough to cross the board and then some) and assume
that anything that exceeds that depth doesn't capture the stones. That way
you only get the wrong solution in a very, very small percentage of the
cases.

    Mark Boon


-----Original Message-----
From: computer-go-bounces@xxxxxxxxxxxxxxxxx
[mailto:computer-go-bounces@xxxxxxxxxxxxxxxxx]On Behalf Of Harry W
Sent: Wednesday, July 14, 2004 5:55
To: drd@xxxxxxxxxxxxxxxxx; computer-go
Subject: Re: [computer-go] citation



> What is your "more specific" definition of a ladder?
>  It's hard for me
> to imagine a definition more "specific" than the one
> John gave.
>

Here's a very good explanation on what a ladder is:
http://senseis.xmp.net/?Ladders

The whole reason when the term "ladder" is used is
because the shape looks like a ladder. Since John's
definition fails to mention this rudimentary fact make
his definition imprecise.

In fact his definition is so generalized, that it
includes situations such as ladders and many more
other situations that are not ladders. this is why I
called the difinition imprecise.

-harry wang



__________________________________
Do you Yahoo!?
New and Improved Yahoo! Mail - Send 10MB messages!
http://promotions.yahoo.com/new_mail
_______________________________________________
computer-go mailing list
computer-go@xxxxxxxxxxxxxxxxx
http://www.computer-go.org/mailman/listinfo/computer-go/

_______________________________________________
computer-go mailing list
computer-go@xxxxxxxxxxxxxxxxx
http://www.computer-go.org/mailman/listinfo/computer-go/