What's wrong with suicide?

[RobertJasiek]

What was before 1949 differs from what is since 1949.

[Cassandra]

What was before 1949 differs from what is since 1949.

In 1949 there had been the first attempt to walk on very unfamiliar ground.
After a period of 40 years walking of 1290 years of Go in Japan there had been a second try in 1989.

If the Japanese had thought it really important (as you, for example, think they should have done - in a Western understanding of "rules", of course), the result would have been flawless.

[RobertJasiek]

How important they took it in 1949 you can see from the 1949 Rules' preamble, which is as serious as some of a constitution.

They wanted to codify Japanese rules in writing. Neither in 1949 nor in 1989 rules theory was advanced far enough to create a flawless rules text for Japanese style rules. This changed only 2004-2006 with my and Chris Dams' research, see

http://home.snafu.de/jasiek/j2003.html
http://home.snafu.de/jasiek/wagcmod.html

and the thereby completed definitions of life. J1989 was a necessary preliminary study for that but the J1989 authors were not skilled enough in mathematical thinking to possibly find the final solution as "quickly" as we did.

In summary, a mere desire to get things right was insufficient - one also needs some suitable background knowledge and lots of time.

[Cassandra]

Well, yes: the struggle is still going on. Why should we not discuss it?

I'm looking forward to do so.

Harleqin, should we use a new topic ?

--------------------------------------------------------

EDITED:

Continued at

Ideas for Japanese-style rules

[cyclops]

........ This changed only 2004-2006 with my and Chris Dams' research, see

http://home.snafu.de/jasiek/j2003.html
http://home.snafu.de/jasiek/wagcmod.html

and the thereby completed definitions of life. ......

In http://home.snafu.de/jasiek/wagcmod.html you mentioned:

Chris Dams has proven: * WAGC-alive equals J2003-alive.

My question: Is there any online text containing this prove and could you please provide a link to it. I tried to find it but failed.

[RobertJasiek]

The proof message:

http://groups.google.de/group/rec.games ... ode=source

The thread:

http://groups.google.de/group/rec.games ... 90e52360b8

Code: Select all

From: Chris Dams <chr...@wn5.nospamplease.nl>
Newsgroups: rec.games.go
Subject: Re: Model for the World Amateur Go Championship Rules
Date: Wed, 12 Apr 2006 20:56:06 +0000 (UTC)
Message-ID: <e1jph6$13q$1@wnnews.sci.kun.nl>
References: <p67q32p0mo82bm1c2h5gpolhs93hncpu52@4ax.com> <e1j9jn$pla$1@wnnews.sci.kun.nl> <27gq32p0vhdvn6j0e5o1fneud7erkaas4a@4ax.com>


Dear Robert,

Robert Jasiek <jas...@snafu.de> writes:

>On Wed, 12 Apr 2006 16:24:23 +0000 (UTC), Chris Dams
><chr...@wn5.nospamplease.nl> wrote:
>>>     In a position, a string of a player is _two-eye-alive_ if the
>>>opponent cannot force no intersection of the string with a
>>>two-eye-formation on. 
>>
>>>     _J2003-alive_ is defined like in J2003 as either uncapturable,
>>>capturable-1, or capturable-2. 
>>
>>>     In a position, a string is _WAGC-alive-in-seki_ if it is
>>>J2003-alive and not two-eye-alive. 
>>
>>>     In a position, a string is _WAGC-alive_ if it is either
>>>two-eye-alive or WAGC-alive-in-seki.  
>>
>>From these definitions it follows that WAGC-alive is identical to
>>J2003-alive.

>I doubt this. If you claim it, then please present a formal proof!

I have to admit that I, at first, interpreted "either" as "or" in the
definition of WAGC-alive. However, I think the identity of J2003-alive
and WAGC-alive is still provable. Proof is given below.

Let us denote

>     In a position, a string is _WAGC-alive-in-seki_ if it is
> J2003-alive and not two-eye-alive. 

as

   WAGC-alive-in-seki == J2003-alive && (!two-eye-alive)

In the same notation we also have from

>     In a position, a string is _WAGC-alive_ if it is either
> two-eye-alive or WAGC-alive-in-seki.  

   WAGC-alive == two-eye-alive ^^ WAGC-alive-in-seki.

Substituting the former into the latter expression, we find

   WAGC-alive == two-eye-alive ^^ (J2003-alive && (!two-eye-alive)).

In propositional calculus this reduces to

   WAGC-alive == J2003-alive || two-eye-alive.

If we now also have the implication two-eye-alive -> J2003-alive if follows
that

   WAGC-alive == J2003-alive.

For the implication two-eye-alive->J2003-alive, imagine that a string is
two-eye-alive. The string can either be uncapturable or not uncapturable.
(1) The string is uncapturable -> It is J2003-alive
(2) It is not uncapturable -> The string is either capturable-1 or
   not capturable-1
   (2a) It is capturable-1 -> It is J2003-alive
   (2b) It is not capturable-1 -> Because the string is two-eye-alive there
         is in every hypothetical-strategy of its opponent a
         hypothetical-sequence in which
         we reach a two-eye-formation that includes one of its intersections.
         For every
         hypothetical-strategy H of the opponent, we choose a
         hypothetical-sequence S(H) in it
         where the oponent reaches a two-eye-formation and subsequently only
         passes. Because the two-eye-formation cannot be capture by only moves
         of its opponent, it consists of permanent stones. In S(H) the
         two-eye-formation that is formed on the captured string has either a
         stone on local-1 of the string or it does not have a stone on local-1
         of the string
         (2b1) If it has a stone on local-1 of the string, it is also on
            local-2.
         (2b2) If it does not have a stone on local-1 of the string,
             then local-1 of the string consists of the one or both
            of the empty intersections of the two-eye-formation. Actually,
            it consists of one of the intersections since if it would consist
            of both, these would have to be adjacent to each other which
            contradicts the definition of a two-eye-formation. So, local-1
            of the string consists of one intersection and during S(H) it
            becomes one of the the empty points of a two-eye-formation. This
            implies that this two-eye formation includes strings that occupy
            the intersections adjacent to local-1. Because local-1 consists of
            one intersections these adjacent intersections where empty or
            occupied by opposing stones. Hence, these intersections belong to
            local-2 of the string.
         In both (2b1) and (2b2) we see that the two-eye-formation that is
         formed in S(H) has permanent stones on local-2 of the string. Hence,
         if every hypothetical-strategy of the opponent of the string there
         is a hypothetical-sequence where a permanent-stone is played on
         local-2. Hence, the opponent cannot force both caputre of the string
         and no local-2 permanent stone. Hence, the string is capturable-2.
         Hence, it is J2003-alive.
Hence, under the assumption that the string is two-eye-alive, we find that
it is J2003-alive. QED.

Best,
Chris

[tromp]

In the "Suicide case", the axiom is pointless and can be left out, as it is always true as a result of the rules. In the "No suicide" case, it is required.

I think either case can be written roughly equally elegantly and concisely, and neither option is really more complex than the other.

The Tromp-Taylor rules have a similar trade-off.
Instead of the two rules

4. Clearing a color is the process of emptying all points of that color that don't reach empty.

7. A move consists of coloring an empty point one's own color;
then clearing the opponent color, and then clearing one's own color.

a version forbidding suicide would probably have only one rule:

7'. A move consists of coloring an empty point one's own color,
such that it reaches empty after emptying all points of the
opponent color that don't reach empty.

Since only the opponent stones need "clearing" there's no need to define
that notion separately. It is arguable which one is more complex.
While the new one is shorter, the old one feels somewhat more streamlined
(an admittedly subjective notion).

My major reason for preferring suicide is to have only one condition
on the legality of playing an empty point (no repetition),
rather than two quite different ones (no repetition and no suicide).

regards,
-John