Re: computer-go: Looking for shicho (ladder) problems

["Antoine de Maricourt" <antoine.demaricourt@xxxxxxxxxx>]

Thanks,

the relationship with PSPACE hardness is not really obvious. Could you say
more about this. Someone reported that you wrote an article on this point,
but I couldn't find it.

Regards,

    Antoine.

----- Original Message -----
From: John Tromp <John.Tromp@xxxxxxxxxxxxxxxxx>
To: <computer-go@xxxxxxxxxxxxxxxxx>
Sent: Tuesday, November 14, 2000 10:04 PM
Subject: Re: computer-go: Looking for shicho (ladder) problems


> On Mon, Nov 13, 2000 at 08:21:07PM +0100, Antoine de Maricourt wrote:
> > Does anybody know where I could find some ladder (shicho) problems on
the
> > net ?
> > The kind that goes all around the board with very deep sequences.
> > Any format, provided it is documented or easy to understand.
>
> You can try the one on the bottom of my go page; click on the
> quantified boolean formula.
> It illustrates that ladders are PSPACE hard.
>
> regards,
>
>
> %!PS                       %  -John Tromp (http://www.cwi.nl/~tromp/)
> 42 42 scale 7 9 translate .07 setlinewidth .5 setgray/c{arc clip fill
> setgray}def 1 0 0 42 1 0 c 0 1 1{0 3 3 90 270 arc 0 0 6 0 -3 3 90 270
> arcn 270 90 c -2 2 4{-6 moveto 0 12 rlineto}for -5 2 5{-3 exch moveto
> 9 0 rlineto}for stroke 0 0 3 1 1 0 c 180 rotate initclip}for showpage