Stable and Periodic discussion

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Stable and Periodic discussion

Post by Book » October 11th, 2022, 8:22 pm

I have completed a draft (User:Book/Sandbox/Stability) of an article intended to replace the current Stable article. It has almost all the content from the current article, though reorganized to emphasize what I believe is the most common usage, along with a history section in support of that usage. I also revised the Periodic article to add what I believe is the common usage of that term, however, Confocal undid the revision so that the two article changes could be discussed in concert. So lets discuss!
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Re: Stable and Periodic discussion

Post by confocaloid » October 11th, 2022, 9:47 pm

The proposed draft begins with the text:
The term stable is used in several contexts. The most general is as follows:

A stable pattern is a periodic pattern for which all future generations can be predicted accurately after one full period without evolving the pattern any further. This includes still lifes, oscillators, spaceships and guns.
I think the claim "a stable pattern is a periodic pattern" is confusing to a reader trying to understand the basics. And also this claim is against common usage. The two words are commonly used with opposite meanings - for example "stable reflector" versus "periodic reflector", "stable circuit" versus "periodic circuit". E.g. see this or this for examples of posts containing both "stable" and "periodic". It is commonly "stable or periodic", rather than "stable and periodic".

---

I doubt if it is a good idea to begin the page with trying to state the most general possible definition (as it seems to do - i.e. "The most general is as follows:"). I think it is better to have more common meanings at the top of the page (as opposed to more general ones). The most general definitions tend to be least useful definitions. And IMO the wiki is a good place to (attempt to) explain existing common usage of terms/words - rather than trying to invent some "generalized" one-size-fits-all definition which is not actually commonly used in real Life.

---

The proposed draft includes a table "A CLASSIFICATION SYSTEM FOR 'LIFE' OBJECTS", which I think is taken from Lifeline Volume 1 with some slight changes (two added links). I believe this classification is interesting in its own right - it would be out-of-context/misplaced, if copied to the page disambiguating different meanings of "stable". Hence I suggest to avoid copying that table to Stable - the classification is not limited to answering the sole question "what means 'stable'?" If necessary, it would suffice to have a single sentence mentioning the classification and linking to the place where it can be found.

---

I oppose moving the current draft to mainspace. Above are some of my objections. It is perfectly possible that other people here will be able to provide more useful suggestions/feedback.

It would be nice to explain better common usages of some or all of these words - but it may be a bad idea to put everything into one page that attempts to talk of many things at once, trying to be a disambiguation and a number of articles and/or glossary pages, all at the same time.

Maybe it's better to keep pages Stable and Periodic sufficiently short, lightweight, quickly readable pages that merely disambiguate between different usages and provide links to other pages?
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Re: Stable and Periodic discussion

Post by dvgrn » October 12th, 2022, 10:04 am

confocaloid wrote:
October 11th, 2022, 9:47 pm
I think the claim "a stable pattern is a periodic pattern" is confusing to a reader trying to understand the basics. And also this claim is against common usage.
I would definitely agree with confocaloid's point here. I've read through Book's draft, and it brings together a lot of good uses of related terms -- and it seems like they could all fit into the "Stable" article.

But the actual standard common-sense definition of "stable" got lost somewhere in the generalization. It seems like the new article should still lead off with the current first sentence:

A pattern is said to be stable if it is a still life or consists of still lifes; in other words, it is a parent of itself.

The draft article seems to lump the words "stable" and "stabilize" together, and there's definitely some justification for that: for example, a lot of our methuselah articles from Acorn to 52513M talk about the eventual "stable pattern", even though of course methuselah ash is hardly ever p1-stable. It's not even reliably p2-stable-excluding-emitted-spaceships. But those sections of those articles really are called "stable pattern", so I'd say that that's a very common usage that should be documented.

I think that I'm usually careful not to use "stable" in the context of a methuselah "going boring"; I try to reserve "stable" to mean "p1" (though no doubt I've slipped up lots of times). But I will definitely say "Stabilized at time T", to mean that that's the point where a methuselah or novelty generator or whatever has become predictable.

So I don't personally think of "stable" and "stabilized" as being interchangeable. If other people are thinking that way also, then maybe the two words shouldn't be conflated.

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Re: Stable and Periodic discussion

Post by confocaloid » October 17th, 2022, 1:31 pm

Note that in the context of methuselahs/long-lasting patterns, there are discussions of final fate, final population, and the resulting pattern is alternatively referred to as the final pattern. Here is an example from the Non-totalistic CA Growth Challenge thread:
Rules:
1. The rule must be in the form of B/S, no custom ruletables, generations, or LTL
2. The pattern cannot be adjustable, so you cannot have a puffer colliding with another.
3. It is allowed for the final pattern to oscillate, just pick a random point in time or find the maximum population.
4. The pattern must stop growing at some point. Infinite growth patterns are not allowed.
An example from the current revision of the wiki page "Glider synthesis":
More challenging is finding a two- or three-directional synthesis for a particular object where few or no parts of the synthesis reactions extend outside the final pattern's bounding box in a particular direction.
An example from Lifeline Volume 3, page 8:
(...) For 'methuselahs' (a term coined by Thompson for any relatively small object with a life ≤ 50 generations), he records the first 20 generations and a picture of the final pattern (with age and census data). (...)
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Re: Stable and Periodic discussion

Post by Book » October 17th, 2022, 1:56 pm

Dealing with periodic on its own (not in the context of stable):

Confocal and I have had a brief edit skirmish with the Periodic article.

I believe that it is missing the most common usage and want to add somethin like:
A pattern is said to be '''periodic''' with period p if it repeats every p generations. This includes, but is not limited to, oscillators, spaceships and guns.
If you disagree, please search the wiki for "periodic"--then explain why this article does not include the usage that floods the search results. If you agree but don't like the edit I propose, by all means improve it.
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Re: Stable and Periodic discussion

Post by confocaloid » October 17th, 2022, 3:17 pm

An interesting discussion that touched the (likely unresolvable) question of whether or not p1 should be considered to count as "periodic": Totally periodic pattern.
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Re: Stable and Periodic discussion

Post by confocaloid » October 17th, 2022, 9:41 pm

Book wrote:
October 17th, 2022, 1:56 pm
If you disagree, please search the wiki for "periodic"--then explain why this article does not include the usage that floods the search results. If you agree but don't like the edit I propose, by all means improve it.
Please give some examples of actual usage that are not covered by either of two definitions from Life Lexicon. I think those two already cover most common uses.
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Re: Stable and Periodic discussion

Post by Book » October 18th, 2022, 1:22 pm

just search the wiki for "periodic"

Category:Natural periodic objects
Category:Small unnatural periodic objects
Category:Unnamed periodic objects
Category:Periodic objects with minimum population 76
and on and on

it seems to me beyond odd that, with all the reference to "period" everywhere, we omit explicitly naming periodic patterns e.g. oscillators, spaceships and guns, for example, as being periodic in the article
why?
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Re: Stable and Periodic discussion

Post by confocaloid » October 18th, 2022, 1:28 pm

Book wrote:
October 18th, 2022, 1:22 pm
just search the wiki for "periodic"

Category:Natural periodic objects
Category:Small unnatural periodic objects
Category:Unnamed periodic objects
Category:Periodic objects with minimum population 76
and on and on

it seems to me beyond odd that, with all the reference to "period" everywhere, we omit explicitly naming periodic patterns e.g. oscillators, spaceships and guns, for example, as being periodic in the article
why?
For these examples, my suggestion is to rename those categories by removing "periodic" from the page names (e.g. "Category:Objects with minimum population 76"), instead of considering this an actual usage.

Any other examples?
Last edited by confocaloid on October 18th, 2022, 2:01 pm, edited 2 times in total.
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Re: Stable and Periodic discussion

Post by Book » October 18th, 2022, 1:35 pm

this isn't about category names, that's just what turns up on the first page of the search
it is about patterns whose period is a core attribute and is mentioned everywhere (for good reason)
again, it seems to me beyond odd that, with all the reference to "period" everywhere, we omit explicitly naming periodic patterns e.g. oscillators, spaceships and guns, for example, as being periodic in the article
why?
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Re: Stable and Periodic discussion

Post by confocaloid » October 18th, 2022, 2:01 pm

Book wrote:
October 18th, 2022, 1:35 pm
this isn't about category names, that's just what turns up on the first page of the search
it is about patterns whose period is a core attribute and is mentioned everywhere (for good reason)
again, it seems to me beyond odd that, with all the reference to "period" everywhere, we omit explicitly naming periodic patterns e.g. oscillators, spaceships and guns, for example, as being periodic in the article
why?
Again, please provide specific examples of uses other than in category names (possibly uses on the forum excluding this meta-discussion), not covered by either of already provided definitions in Periodic. I already looked through many search results on the wiki. I think category names should be shortened by removing the word "periodic".
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Re: Stable and Periodic discussion

Post by Book » October 18th, 2022, 2:09 pm

I think category names should be shortened by removing the word "periodic".
which would make those names ambiguous

Again, again, this isn't about category names, it is about patterns whose period is a core attribute and is mentioned everywhere (for good reason)
again, it seems to me beyond odd that, with all the reference to "period" everywhere, we omit explicitly naming periodic patterns e.g. oscillators, spaceships and guns, for example, as being periodic in the article
why?
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Re: Stable and Periodic discussion

Post by confocaloid » October 18th, 2022, 2:12 pm

Please give specific examples of uses.
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Re: Stable and Periodic discussion

Post by dvgrn » October 18th, 2022, 2:52 pm

confocaloid wrote:
October 18th, 2022, 1:28 pm
For these examples, my suggestion is to rename those categories by removing "periodic" from the page names (e.g. "Category:Objects with minimum population 76"), instead of considering this an actual usage.
Yikes. These category names are an actual common usage of the word "periodic". So we certainly shouldn't be renaming those existing categories to pretend that we don't use the word "periodic" that way.

I liked Book's second edit attempt best, since it mentions p=1 as a "trivial" option, which seems to be correct. For example, https://conwaylife.com/wiki/Category:Periodic_objects_with_minimum_population_15 includes 15-bent-paperclip in the list along with lots of oscillators. I.e., still lifes are trivial oscillators, not usually worth mentioning as such, but they still show up in the category.

Putting that general definition as the first item in the list seems to make sense, as confocaloid suggested in a revert comment.

I'm not sure I'd include guns in the "oscillators, spaceships, and guns" list, though. From my point of view, guns are technically growing objects, not periodic objects... specifying "capped guns" would fix that problem, but it might be better to just leave out the mention of guns.

Maybe my version would be just "This includes still lifes (trivially, with p=1), oscillators, and spaceships." If we're using "periodic" in this most general sense... how can something be periodic but not be a still life, oscillator or spaceship? Why would the "but not limited to" clause be needed?

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Re: Stable and Periodic discussion

Post by Book » October 18th, 2022, 3:24 pm

If we're using "periodic" in this most general sense... how can something be periodic but not be a still life, oscillator or spaceship? Why would the "but not limited to" clause be needed?
The only reason I added the "not limited to" was CYA, in case there was some sort of pattern described as periodic which I am unaware of.
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Re: Stable and Periodic discussion

Post by confocaloid » October 18th, 2022, 3:35 pm

dvgrn wrote:
October 18th, 2022, 2:52 pm
confocaloid wrote:
October 18th, 2022, 1:28 pm
For these examples, my suggestion is to rename those categories by removing "periodic" from the page names (e.g. "Category:Objects with minimum population 76"), instead of considering this an actual usage.
Yikes. These category names are an actual common usage of the word "periodic". So we certainly shouldn't be renaming those existing categories to pretend that we don't use the word "periodic" that way.

I liked Book's second edit attempt best, since it mentions p=1 as a "trivial" option, which seems to be correct. For example, https://conwaylife.com/wiki/Category:Periodic_objects_with_minimum_population_15 includes 15-bent-paperclip in the list along with lots of oscillators. I.e., still lifes are trivial oscillators, not usually worth mentioning as such, but they still show up in the category.

Putting that general definition as the first item in the list seems to make sense, as confocaloid suggested in a revert comment.

I'm not sure I'd include guns in the "oscillators, spaceships, and guns" list, though. From my point of view, guns are technically growing objects, not periodic objects... specifying "capped guns" would fix that problem, but it might be better to just leave out the mention of guns.

Maybe my version would be just "This includes still lifes (trivially, with p=1), oscillators, and spaceships." If we're using "periodic" in this most general sense... how can something be periodic but not be a still life, oscillator or spaceship? Why would the "but not limited to" clause be needed?
Well, for me the presence of still lifes, guns, and especially "but not limited to" seems dubious - if these are included, the next question would be probably "what is not included"?

My suggestion in the edit summary was to put more common meanings on the top of the page, rather than more general ones. I think the two meanings already given on the page are more common than the proposed generalisation - so even if the proposed third definition gets included, I think it should not be on the top.

The current category description of Category:Periodic objects with minimum population 15 says: "This category contains all notable strict still lifes, oscillators, and spaceships with a minimum population of 15 in at least one phase." What would change if the category was renamed to Category:Objects with minimum population 15? If there is no substantial difference, I would prefer shorter category names without "periodic", as an attempt to reduce associated confusion and make search results in the wiki more relevant.

Note also that there are other words sometimes used with related/overlapping meanings - e.g. "oscillating".
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Re: Stable and Periodic discussion

Post by Book » October 18th, 2022, 4:24 pm

I intend to add the following to the article as the third context:
  • A pattern is periodic with period p if it repeats every p generations. This includes still lifes (trivially, with p=1), oscillators, and spaceships.
(edited to replace "said to be" with "is")

I do not care if it is the first or last of the three items. Seems a moot point to me.
Last edited by Book on October 18th, 2022, 5:35 pm, edited 1 time in total.
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Re: Stable and Periodic discussion

Post by confocaloid » October 18th, 2022, 4:33 pm

Book wrote:
October 18th, 2022, 4:24 pm
I intend to add the following to the article as the third context:
  • A pattern is said to be periodic with period p if it repeats every p generations. This includes still lifes (trivially, with p=1), oscillators, and spaceships.
I do not care if it is the first or last of the three items. Seems a moot point to me.
Could you please quote/link to actual examples of usage - where, when and in what context some pattern is "...said to be periodic with period [something]" (in the same way as in the proposed wording)? (Excluding this meta-discussion, of course.)
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Re: Stable and Periodic discussion

Post by Book » October 18th, 2022, 5:36 pm

nope; see edit above
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Re: Stable and Periodic discussion

Post by confocaloid » October 18th, 2022, 5:57 pm

Interestingly, the only place in the wiki where I could find "periodic with period" is in a footnote in this page: Life128 and vlife. If it was the only instance, I think it would not be sufficient to mention this usage at all in the wiki.

Fortunately, the same wording appears on Catagolue object pages for things whose apgcodes begin with "x" (still lifes, oscillators and constellations consisting of any number of these, as well as spaceships and flotillae consisting of any number of spaceships all moving in the same direction with the same speed). For example, the page for loafer says "This pattern is periodic with period 7."

I think this makes this wording sufficiently common to mention it in the wiki (even though the wording is automatically generated and is the same regardless of whether the period is 1 or greater than 1 - and I believe the distinction between stable things and periodic things is otherwise common and useful).
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Re: Stable and Periodic discussion

Post by dvgrn » October 18th, 2022, 6:10 pm

Book wrote:
October 18th, 2022, 3:24 pm
The only reason I added the "not limited to" was CYA, in case there was some sort of pattern described as periodic which I am unaware of.
Ah, got it. I guess I'd rather have the statement be short and clear -- and possibly slightly wrong, with further additions to be made later by whoever can think of another exception, in proper wiki fashion.

Adding those extra words gives the appearance of information that isn't really there -- "the phrase must have been added for a reason, so there must be some other category!"
confocaloid wrote:
October 18th, 2022, 3:35 pm
The current category description of Category:Periodic objects with minimum population 15 says: "This category contains all notable strict still lifes, oscillators, and spaceships with a minimum population of 15 in at least one phase." What would change if the category was renamed to Category:Objects with minimum population 15? If there is no substantial difference, I would prefer shorter category names without "periodic", as an attempt to reduce associated confusion and make search results in the wiki more relevant.
Seems like that would increase confusion, not decrease it, as well as being a lot of work. Those categories currently do not include, for example, methuselahs with minimum population 15 -- and they shouldn't, precisely because of the "periodic" limitation.

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Re: Stable and Periodic discussion

Post by Book » October 18th, 2022, 6:49 pm

What Confocal has added to the wiki is ok with me, but it seems a strange and obtuse way to say something which is simply and obviously true:
A pattern is periodic with period p if it repeats every p generations. This includes still lifes (trivially, with p=1), oscillators, and spaceships.
Seems to tie it too much to Catagolue when it is generally true. Which is why all those categories have the names they do. But good enough is good enough.
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Re: Stable and Periodic discussion

Post by confocaloid » October 18th, 2022, 6:55 pm

Book wrote:
October 18th, 2022, 6:49 pm
What Confocal has added to the wiki is ok with me, but it seems a strange and obtuse way to say something which is simply and obviously true:
A pattern is periodic with period p if it repeats every p generations. This includes still lifes (trivially, with p=1), oscillators, and spaceships.
Seems to tie it too much to Catagolue when it is generally true. Which is why all those categories have the names they do. But good enough is good enough.
(For what it's worth) I do not like the repetition in "periodic with period". If the pattern is an oscillator, or when talking about a subset of cells of a pattern, I think an alternative way to say it would be "oscillates with period...".

Just because something is "technically true", does not mean it should be described in the wiki.
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Re: Stable and Periodic discussion

Post by dvgrn » October 18th, 2022, 7:32 pm

confocaloid wrote:
October 18th, 2022, 6:55 pm
Just because something is "technically true", does not mean it should be described in the wiki.
Why is "technically true" in quotes? What we've been talking about is the p=1 case being "trivially true", and it's important to mention that in passing because it is a non-obvious convention that in fact is the accepted convention on the LifeWiki (as evidenced by the 15-cell periodic pattern category mentioned above.)

I'm going to go ahead and replace confocaloid's latest edit to the Periodic page, since it seems almost completely unreadable to me, as well as irrelevant (too specific to one artificial machine-generated usage on Catagolue):
confocaloid wrote:On Catagolue object pages for patterns whose apgcode begins with "x" (including still lifes, oscillators, and spaceships), an automatically generated description includes the line "This pattern is periodic with period (p).", with "(p)" replaced by the actual period of the object.[note 1]
I'll replace it with this:
A periodic pattern oscillates with period p if it repeats every p generations. This includes still lifes (trivially, with p=1), oscillators, and spaceships.
EDIT: In the now-third item in the list, should the ns maybe be replaced by ps for consistency's sake?

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Re: Stable and Periodic discussion

Post by Book » October 18th, 2022, 7:57 pm

n to p?
makes sense to me
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