# Group, Seki, Eyespace: Definitions

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### Robert Jasiek

Nov 18, 2003, 12:37:42 PM11/18/03
to
SL tries to define some basic terms unequivocally. Below I provide
unequivocal definitions under the assumption that the Japanese 2003
Rules would already be in their final, unequivocal version.

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

***

Definition: A _black-group_ is the union of all black-strings of a
black-region.

Definition: A _white-group_ is the union of all white-strings of a
white-region.

Definition: A _group_ is either a black-group or a white-group.

Note: For other purposes one might want to define group differently.

Definition: An _in-seki-space_ is a dame and, recursively, any

Definition: A _seki_ is the union of all strings of an in-seki-space.

Definition: A group is _independently-alive_ if it is not part of a
seki.

Definition: A _black-eye_ is a black-eye-point and, recursively, any

Definition: A _white-eye_ is a white-eye-point and, recursively, any

Definition: An _eye_ is either a black-eye or a white-eye.

Definition: A _black-eye-space_ of a black-group is the union of all
black-eyes of the black-group's region.

Definition: A _white-eye-space_ of a white-group is the union of all
white-eyes of the white-group's region.

Definition: An _eye-space_ is either a black-eye-space or a
white-eye-space.

***

The definitions apply under the Japanese 2003 Rules and for some
final-position. The latter is created trivially. For other
rulesets, some modifications of the rules would be necessary. It
is no problem if the scoring system should differ.

--
robert jasiek

### Chris Lawrence

Nov 18, 2003, 2:18:25 PM11/18/03
to
On Tue, 18 Nov 2003, Robert Jasiek wrote:

> SL tries to define some basic terms unequivocally.

I don't think so. It tries to explain what the terms mean, in plain
English.

> Below I provide unequivocal definitions under the assumption that the
> Japanese 2003 Rules would already be in their final, unequivocal
> version.

[snip]

None of those mean anything to me. They don't help me understand what
seki is. It's like somebody asking what email is and answering them
with RFC2822 (http://www.ietf.org/rfc/rfc2822.txt?number=2822)

--
Chris

### Nick Wedd

Nov 18, 2003, 5:15:33 PM11/18/03
to
In message <Pine.WNT.4.58.03...@holodeck3.holosys.wlan>,
Chris Lawrence <new...@holosys.co.uk.invalid> writes

That is an excellent analogy! However I fear it will be wasted on
Robert, who will have noted that URL in case someone asks him what email
is.

Nick
--
Nick Wedd ni...@maproom.co.uk

### Robert Jasiek

Nov 19, 2003, 3:00:14 AM11/19/03
to

Chris Lawrence wrote:
> > SL tries to define some basic terms unequivocally.
> I don't think so. It tries to explain what the terms mean, in plain
> English.

Maybe SL also tries that. However, recently there have been some
pages on SL that try to define some go terms unequivocally.

> > Below I provide unequivocal definitions under the assumption that the
> > Japanese 2003 Rules would already be in their final, unequivocal
> > version.

> None of those mean anything to me. They don't help me understand what
> seki is.

I will explain their application in a book about Japanese rules.
If you are interested in practical go knowledge, then surely
there are easier ways to understand things than to understand
them completely at once.

tel <tel....@spamgourmet.com> wrote:
>> Definition: A group is _independently-alive_ if it is not part of a
>> seki.

Thx, you are right! The definition must be:

A group is _independently-alive_ if it is neither part of a

(In earlier versions of the rules I had only black-regions
with alive black-strings. For the rules, it has not been
necessary to exclude dead strings. However, for the above
term excluding them becomes useful again. Sigh:) It would
also be possible to define group so as not to include dead
strings.)

--
robert jasiek

### Chris Lawrence

Nov 19, 2003, 7:22:30 AM11/19/03
to
On Wed, 19 Nov 2003, Robert Jasiek wrote:

> > None of those mean anything to me. They don't help me understand what
> > seki is.
>
> I will explain their application in a book about Japanese rules.
> If you are interested in practical go knowledge, then surely
> there are easier ways to understand things than to understand
> them completely at once.

You don't understand what I mean. The definitions you posted don't help
me to understand *anything* about seki, eyespace, etc. They were just
noise. Even with my best rules hat on I got nothing from them. They
either read as stating the obvious or missing the point but they didn't
define anything.

--
Chris

### Richard Lancashire

Nov 19, 2003, 8:00:06 AM11/19/03
to
Robert Jasiek <jas...@snafu.de> wrote in message news:<3FBA58E6...@snafu.de>...

> SL tries to define some basic terms unequivocally. Below I provide
> unequivocal definitions under the assumption that the Japanese 2003
> Rules would already be in their final, unequivocal version.
>
> http://home.snafu.de/jasiek/j2003.html

Robert,

1) I presume that a 'black intersection' is an intersection on which a
black stone has been placed?

2) Resignation is not mentioned. Is it not necessary for completeness?

Regards
Rich

### Robert Jasiek

Nov 19, 2003, 8:08:36 AM11/19/03
to

Richard Lancashire wrote:
> > http://home.snafu.de/jasiek/j2003.html

> 1) I presume that a 'black intersection' is an intersection on which a
> black stone has been placed?

Yes. I will look at such stylistic details a little later.

> 2) Resignation is not mentioned. Is it not necessary for completeness?

I consider that to be part of tournament rules. Therefore I do
not treat it in the rules of play. Similarly, a lot of other
tournament rules are not included.

--
robert jasiek

### Robert Jasiek

Nov 19, 2003, 8:29:40 AM11/19/03
to

Chris Lawrence wrote:
> You don't understand what I mean. The definitions you posted don't help
> me to understand *anything* about seki, eyespace, etc. They were just
> noise.

The definitions (as definitions alone) are not intended to help
YOU to understand the concepts seki, eyespace, etc. They are
aimed at those people that are interested in complete definitions.
If you are not interested in complete definitions, then ignore
all (complete) definitions:)

> Even with my best rules hat on I got nothing from them.

It is necessary to understand the essence of the Japanese 2003
Rules to get meaningful applications for example shapes. If
you do not understand a significant amount of those rules, then
either ignore them, ask specific questions, or wait for my book
about them, in which I shall explain everything in detail and also
with examples.

The topic is very difficult; so you should not expect to
understand things quickly. I needed 10 years of general rules
study and almost half a year of specific study to understand
those things. So how can you expect quick understanding?

> They
> either read as stating the obvious or missing the point but they didn't
> define anything.

The nice thing is that the Japanese 2003 Rules are so
extraordinarily powerful that defining those go terms
looks as if everything were obvious.

You could get the wrong impression that they do not define
that are defined elsewhere. Maybe I have chosen the words
of that the terms consist so particularly well that you
are familiar with them. My fault:) I might have said

--
robert jasiek

### Ted S.

Nov 19, 2003, 9:22:56 AM11/19/03
to
Somebody claiming to be Robert Jasiek <jas...@snafu.de> wrote in
news:3FBB230E...@snafu.de:

>I will explain their application in a book about Japanese rules.
>If you are interested in practical go knowledge, then surely
>there are easier ways to understand things than to understand
>them completely at once.

Does this mean you're admitting that what you're undertaking is
impractical? :-p

--
Ted S.: change .spam to .net to reply by e-mail
When will I learn? The answers to life's problems aren't at the bottom of
a bottle. They're on TV! --Homer Simpson
<http://www.snpp.com/episodes/7G04.html>

### Robert Jasiek

Nov 19, 2003, 10:51:33 AM11/19/03
to

"Ted S." wrote:
> Does this mean you're admitting that what you're undertaking is
> impractical? :-p

Have I ever spoken differently about Japanese rules? ;(

--
robert jasiek