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The 20 most recent postings on Sensei's Library (not for the faint of heart :o)

 
Page: Ladder · Topic: Origin of "ladder"
47.155.33.231: Origin of "ladder" (2024-03-26 02:24) [#12427]

Does anyone know who first used the term ladder and when?

Unkx80: Re: Simple concise textual definition. (2024-03-17 12:24) [#12426]

No worries. :) If there is a definition of alive or pass-alive that uses construction rather than the inability to capture, then the community would have come out with one by now. Therefore, I suspect a definition by construction doesn't really exist.

However, I do admit that operationally, the resist capture definition is difficult to apply. Therefore people came out with various heuristics, of which many are of the form of one-sided implications (if certain properties are satisfied, then the group is alive). Examples include:

  • If a chain has two real eyes, then it is pass-alive. (See recognizing an eye for a heuristic for determining whether an eye is real.)
    • If a group can obtain two real eyes with perfect play by the defender, then the group is alive. (The part on perfect play is typically omitted and implied in discussions.)
  • If a chain is part of a seki, then it is alive but not pass-alive.

You can start by learning and applying such constructive heuristics first, then expanding your knowledge by figuring out how to make or destroy eyes (this is a gigantic topic), and learning exceptions such as false eye life. I would say, the ability to make two eyes or to make seki covers the vast majority of the cases, so gun for those first.

All the best! :)

xela: Re: Simple concise textual definition. (2024-03-16 23:48) [#12425]

Yes, we've got something like a 2,000 year history behind us, plus just a few years since AI turned everything upside down. No fear of running out of interesting things to learn :-) Keep enjoying yourself, and keep asking questions!

deMangler: Re: Simple concise textual definition. (2024-03-15 17:54) [#12424]

My use of the phrase "directly or indirectly" is redundant now that I think of it. Connected is connected. Thanks for the feedback that really helps, the effort in trying to create a definition has helped and learning more why this is not straightforward is helping more. :) Also it is great to be reminded that go is always rewarding of more attention and analysis, and there is so much to discover from other peoples work on it. Not many games like that!

deMangler: Simple concise textual definition. (2024-03-15 17:50) [#12418]

As a beginner, and a coder who thinks textually, I was looking for a very simple logical, textual definition of a living group, from the point of view of the construction (has these properties) rather than the function (ie to resist capture). I couldn't find one that worked for me.

Eventually through my effort and through checking with language models I came up with this: "all stones in the living group must be connected, directly or indirectly to each other, or to at least two surrounded liberties" This was the simplest complete textual definition I could come up with, and it really helped me understand the living construct. So i'm putting it in this discussion, maybe a more experienced player/editor might know if this is useful to add to the site somewhere.

  • edit*

Thanks for the replys. Attempting the definition was helpful to my understanding, and reading more about why it isn't that simple is helping more! :)

Malcolm: Re: Simple concise textual definition. (2024-03-15 14:58) [#12423]

In the above, I should have used the term pass-alive rather than unconditional life because that would have been clearer.

Anyway deMangler, I saw your SL page and I wish you all the best in your journey! Don't worry at all about losing games in the beginning. You may have heard of proverbs like the best way to start at Go is to lose 100 games as quickly as possible.

You wrote in your SL page that you lose many games through not recognising false eyes. That's a common thing for beginners. There are some common simple situations that one can become familiar with quickly. I recommend having a look at Capture Three To Make An Eye - and I was thinking of a similar, related page Capture Two To Make A Half Eye? which doesn't exist at the moment - it may or may not exist at some point in the future.

I saw Xela's comments which are very sensible. I feel that for most beginners, trying to get precise / rigorous / formal definitions for some things is not be the best approach. Indeed, the New Zealand rules are short and precise - and they don't mention concepts such as life and death; they don't need to.

xela: Counterexample (2024-03-15 12:32) [#12422]

Oh, another thing. In this diagram, all black stones are connected to two liberties, but the group is not alive.

[Diagram]
 


Or, by "surrounded liberties", did you mean two distinct, separated liberties? Then consider this:

[Diagram]
 

Not alive by your definition? It's not alive in the strict sense of being pass-alive, but in an actual game you would stop adding stones to it at this point and treat it as alive anyway.

xela: Re: Simple concise textual definition. (2024-03-15 12:19) [#12421]

I'm sorry to tell you that what you're looking for simply doesn't exist! I looked for it too when I started learning go :-)

First you have the theory. Yes, it's true that if all stones are "connected" to two liberties, roughly speaking, then the group is alive. (Unkx80 and Malcolm have linked to more precise versions of this statement.) But this is not the only way to live! Exceptions in real games are rare, but if you want your definitions to be logically correct then you have to deal with things like moonshine life and hanezeki.

Then there's the practical side. It's common to end the game with some groups that surround large empty spaces but don't have two distinct eyes. Usually, two experienced players will agree that these groups are alive beyond all reasonable doubt, but won't require a mathematical or logical proof that they are 100% alive. (Unless the surrounded space is so huge that an invasion is possible, in which case one player won't pass but will have a go at invading.)

If you're playing with Chinese rules (or some other form of area scoring), you could of course fill in most of the space until you've created a pass-alive group, and there you have your mathematical proof. But this is time-consuming and annoying. If you make a habit of doing this past the beginner stage, people won't want to play with you. And under Japanese rules or territory scoring, you will also lose a lot of points by doing this. So at some point you have to get used to living with a tiny amount of ambiguity.


If you like simple logical, textual definitions, then you'll probably enjoy the New Zealand rules! They're not quite what you're looking for, but they are in a sense very beautiful.

Malcolm: Re: Simple concise textual definition. (2024-03-15 10:40) [#12420]

Even if the "or" were changed to "and", following Unkx80's remarks, and something were done to disambiguate the word "indirectly", it still would not be a satisfactory definition. Because it also needs something about non-adjacency of two or more surrounded empty intersections, in order to exclude single eyes larger than one intersection.

If we're talking about "unconditional life" rather than "life", then it seems to me that Benson's theorem may be the best available purely textual definition along the lines you're looking for.

Unkx80: Re: Simple concise textual definition. (2024-03-15 09:34) [#12419]

The term live or alive can include seki which you missed. Further, alive can also include the cases where the defender's group cannot be captured regardless of how it is being attacked, provided that the defender mounts a perfect defense - see Alive - Introductory for an example. In this aspect, a group that is alive can become dead if the defender fails to defend correctly, or fails to respond to an attacking move at all (perhaps to resolve a ko, in which case the attacking move is a ko threat).

I guess what you are trying to define is pass-alive in a mathematically rigorous manner. However, there are at least two problems:

  • You do not define the term indirectly.
  • You seem to be describing properties of a pass-alive group, but due to the final or world in your sentence, merely satisfying these properties does not guarantee that a group is pass-alive. However, merely changing the final or to and appears to be insufficient (depending on what you mean by indirectly).
31.217.174.23: Re: Maybe it is time for Arno Hollosi and Morten Pahle to intervene here. (2024-03-09 00:02) [#12417]

So, if there is still a disagreement, what are you all doing? Why do you add fuel to the fire?

Everyone must read this [ext] https://phk.freebsd.dk/sagas/bikeshed/#the-bikshed-email.

Here are two excerpts from the e-mail:

Excerpt 1

It was a proposal to make sleep(1) DTRT if given a non-integer
argument that set this particular grass-fire off.  I'm not going
to say anymore about it than that, because it is a much smaller
item than one would expect from the length of the thread, and it
has already received far more attention than some of the *problems*
we have around here.

The sleep(1) saga is the most blatant example of a bike shed
discussion we have had ever in FreeBSD.  The proposal was well
thought out, we would gain compatibility with OpenBSD and NetBSD,
and still be fully compatible with any code anyone ever wrote.

Yet so many objections, proposals and changes were raised and
launched that one would think the change would have plugged all
the holes in swiss cheese or changed the taste of Coca Cola or
something similar serious.

Excerpt 2

A bike shed on the other hand.  Anyone can build one of those over
a weekend, and still have time to watch the game on TV.  So no
matter how well prepared, no matter how reasonable you are with
your proposal, somebody will seize the chance to show that he is
doing his job, that he is paying attention, that he is *here*.

In Denmark we call it "setting your fingerprint".  It is about
personal pride and prestige, it is about being able to point
somewhere and say "There!  *I* did that."  It is a strong trait in
politicians, but present in most people given the chance.  Just
think about footsteps in wet cement.

If you continue like this, Arno Hollosi and Morten Pahle will have to intervene.

Dieter: Re: ((no subject)) (2024-03-08 15:10) [#12416]

I have no interest in a fight. Like you, I have an interest in the well being of this site. We agree the programming language pages are superfluous here. Others think they have value. When in doubt, we leave things about. That's how Morten and Arno have wanted it.

The "minor edit" is not there to perform a disputed action in disguise. It's there to perform a non-contentious action so that it doesn't mess up the list of meaningful changes.

Dieter: Re: Maybe it is time for Arno Hollosi and Morten Pahle to intervene here. (2024-03-08 15:01) [#12415]

I should clarify that we are a group of librarians who keep an eye on this site. That includes xela, PJ and myself. One of the things we do is undo damage/vandalism, for which searching edits by IP is an obvious device.

It can be argued your actions were not vandalism, but they were part of a non-agreed removal of content. Like I said before, I actually agree with the reasons for removal of most. But that's just me and as a group we're divided on the subject. The original creators of this site have always held a liberal spirit towards content and format, so we honor that.

As you may have noticed, your contributions which were not part of the one sided removal, were not reverted. You are absolutely welcome on this site. It's a collaborative one, so nothing goes the way each of us want all the time.

2003:00dd:df31:5b18: Re: Maybe it is time for Arno Hollosi and Morten Pahle to intervene here. (2024-03-08 14:34) [#12411]

PJTraill: What I did was to check all recent changes for removal of information without consensus, and to repair the damage. Oddly enough, all such changes came from the same IP range.

My intention was to preserve information that could be of value to some users. I understand that may have upset that editor, but they were the ones making unilateral judgements on what was worth keeping.

I do not want them to go away, as they have done useful work as well. I want them to be polite and cooperative, and preferably to use a registered user name.

As Dieter said, your tone is unjustified; you also misinterpret my actions, perhaps wilfully. High-handedly removing information is more like editing “according to ones beliefs and feelings” than is restoring information many have assembled.

My experience with software is on the record but seemed only marginally relevant to my judgements in this matter.

PJTraill: Re: Female -> Women's (2024-03-08 14:17) [#12414]

I agree that it sounds more natural in that case, and probably many others. I am not sure if it is feasible or wise to bulk edit automatically, but I think it is probably not too much trouble to fix the main points of interest manually.

I see that we have/had

  • these pages:

FemaleHoninbo FemaleStudentHoninbo AllJapanFemaleAmateurChampionship FemaleKisei FemaleStrongest FemaleZuiqiang? FemaleMingren ChinaFemaleGuoshou? HuangLongshiFemaleMingren? TeikeiCupFemaleLegends FemaleTaiwanMingren? FemaleXinrenWang JALFemaleHayaGo SamsungCupKoreanfemalepreliminaries SupremeFemalePlayer FemaleSiptan

  • these aliases:

FemaleDaiwaCup FemaleGuoshou FemaleKisung FemaleKuksu FemaleMeijin FemaleNationalSportsMeeting FemaleSaikyo FemaleSupremePlayer FemaleTachiaoiCup TaiwanFemaleStrongest

  • and 581 pages containing the text “female”.

I have just successfully renamed FemaleSiptan to Women's Siptan to see if any difficulties are to be expected. No promises, but perhaps I shall get round to renaming others soon — if no-one else takes it upon them first! I did not create an alias, which did not seem necessary in that case. One might use an alias if unexpected difficulties crop up, but otherwise I think it would be a bit pointless.

I find it a slight shame that an apostrophe in a page title has to be ' rather than (I think), but we can live with that!

DudleyMoore: Female -> Women's (2024-03-08 09:06) [#12413]

Elsewhere on the internet, John Fairbairn pointed out that a translation such as Female Kisei was wrong, Women's Kisei is the normal choice in the english world. Is it possible to do a bulk fix for this?

The choice of the term female would be more normal in some kind of scientific literature. Used here it sounds wrong to any native speaker. It is probably something we native speakers have all noticed before, but believed either to be some weird convention in translation, or were just to restrained to speak up about it.

PJTraill: Re: Maybe it is time for Arno Hollosi and Morten Pahle to intervene here. (2024-03-08 08:45) [#12412]

Sorry, forgot I was not logged in on this device!

31.217.174.95: Re: Maybe it is time for Arno Hollosi and Morten Pahle to intervene here. (2024-03-08 03:29) [#12410]

You searched for pages that were last edited by the same person and you edited those pages with the intention to provoke, to bother, and to annoy that person. You want that person to go away. You did not present evidence and you proved nothing. You have no arguments or counterarguments. Those edits were clearly made in haste and out of spite. We are not here to fight. We are not here to edit according to our beliefs and feelings. You are a man who has been working with computers for decades. All the software page edits should have been self-explanatory to you. It is a shame that so many here are dishonest, shameless, and spiteful.

Dieter: Re: Maybe it is time for Arno Hollosi and Morten Pahle to intervene here. (2024-03-08 02:02) [#12409]

There is absolutely no point in this anonymous defamation of well established librarians. Some introspection is due.

PJTraill: Re: Maybe it is time for Arno Hollosi and Morten Pahle to intervene here. (2024-03-07 23:06) [#12407]

I am sorry to hear that you feel provoked: by what? Did you forget to log in, or are you another anonymous contributor?


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