Can we substantiate this claim?

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dbell
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Re: Can we substantiate this claim?

Post by dbell » June 9th, 2022, 9:16 pm

Here is the unusual spaceship used in the fly-by deletion of a pond.

Code: Select all

x = 89, y = 53
#C A fly-by deletion of a pond using an unusual spaceship.
#C From a collection by Jason Summers in 2001.
23boo16bo5bo18bo5bo5bo$22bobbo14b3o3b3o7b3o6b3o3b3o3b3o$22bobbo14boboo
boobbo5bobbo6bobooboobbobobboo5bo$23boo6bo9bobo4b3o3b3obbo6bobobobboob
obboo4b3o$30b3o8b3obobobo8b6obbo3bobobobobbo5boboo$bo15bo11bobboo3b8ob
5obobbo4bobo3b3o5b3o3bo5b3o$3o6bo6b3o10bobboo3boboobbo5bobobbo9bo4boob
o7bo5b3o$oboo4b3o5boboo11bobbobbobo4bobbo15bo7bo8b4obboo$b3o3bobboo5b
3o7bo3bobbo9boo30bo3bo$b3obbobobbo5b3o11b4o$boo7bob3obboo12booboo$4boo
6boo3boo14bobbo$bbobbo6bo3boo12bobbobbob3o$bo11bo17bo6boboo$bo35bobbob
oo$40bobo$19bo12bo6booboboo$18b3o10b3o8boboo$18boboo8boobo8bobbo$19b3o
8b3o9booboo$19b3o8b3o6booboobbo$19b3o9boo8boobbobo$19boo20boo$$42bobo$
17bo23bob3o$16b3o21boobobbo$15boobo20bobo$15b3o21bo5bo$15b3o20bo4bobo$
16boo19boo4bobo$37boo$38bobbo$$38b3o$37bobbo$37b5o$37boo$38boobbo$39bo
5bo$38bo5b3o$37boo5boboo$38bo6b3o$38bo6boo$39boboo$40b3o$$43bo$44bo$
44boo$44b3o$44b3o$44boo!
A smaller spaceship with the same sparks can probably be found.

BCNU,
-dbell

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Re: Can we substantiate this claim?

Post by GUYTU6J » June 11th, 2022, 8:06 am

dbell wrote:
June 9th, 2022, 9:16 pm
Here is the unusual spaceship used in the fly-by deletion of a pond.

Code: Select all

A 2c/4 behemoth
Does it mean when the Life Lexicon/LifeWiki entries for Fly-by deletion and Reanimation were written, the circumstance allowed period-4 spaceships only (and no higher periods like p32 mentioned here)?

---

In Rephaser, Entity Valkyrie wrote:
For example, two bumpers in a 180-degree turn can be used as a rephaser to get a glider stream of repeat time 52 to the same place that two Snarks could, but arriving at a time impossible to do with the Snark.
Why period 52? That is apparently higher than the repeat time of both Snark and bumper. There must be some omitted context for the statement.
Why do most 2-state OCA rules tend to get a diminishing span of interest and go into oblivion, like lost civilizations leaving little records for their beauty and power?

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Re: Can we substantiate this claim?

Post by Book » June 18th, 2022, 8:14 pm

This from the Wire article:
Oscillators have been found that inject signals of various periods including 9, 10, and 11 into a 5c/9 wire.[citation needed]
Can we substantiate?

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Re: Can we substantiate this claim?

Post by dvgrn » June 18th, 2022, 9:31 pm

Book wrote:
June 18th, 2022, 8:14 pm
This from the Wire article:
Oscillators have been found that inject signals of various periods including 9, 10, and 11 into a 5c/9 wire.[citation needed]
Can we substantiate?
Sure, that's all in Dean Hickerson's signal-injector collection, I believe.

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Re: Can we substantiate this claim?

Post by carsoncheng » June 22nd, 2022, 9:20 am

In the wiki article for 144P24, one unreferenced statement is present without any references or associated RLE.
"the stable form of the crown wasn't found until two months later"

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Re: Can we substantiate this claim?

Post by pzq_alex » June 22nd, 2022, 12:06 pm

carsoncheng wrote:
June 22nd, 2022, 9:20 am
In the wiki article for 144P24, one unreferenced statement is present without any references or associated RLE.
"the stable form of the crown wasn't found until two months later"
crown lists the discovery date as Jan 3, 1995, while the discovery date of 144P24 is Nov 20, 1994.
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Stop turning this forum into a place for politics. Please.

Code: Select all

x=4,y=3,rule=B3S2-i3-a4ciz5j6c8
bo$3o$ob2o!

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Re: Can we substantiate this claim?

Post by HartmutHolzwart » June 23rd, 2022, 1:58 am

On an upper bound for the average density of periodic agars for period n, here's two mails from the life list:
-4399 From: Hartmut Holzwart
Date: Fri, 18 Sep 92 15:37:20 +0200
Subject: Re: density of successive generations of life


In a recent message Dean gave a proof that the average density of two
successive generations in the game of life is at most 6/11 and
conjectured that the possible pairs of densities (d,e) lie in the
convex hull of the points (0,0), (1,0) and (1/3,1).
I briefly summarize and rephrase the important part of his proof:
Denote by l_i and d_i the number of living
respectively dead cells with i ON neighbors in generation 0. Then there are
8*l_0 + 7*l_1 + ... + l_7 = d_1 + 2*d_2 + ... + 8*d_8 (*)
pairs of cells containing one ON and one OFF cell.
Now the number of living cells in gen. 0 is l_0 + ... + l_8, while the
number of living cells in gen. 1 is l_2 + l_3 + d_3. From equation (*)
we get 3*d_3 <= 8*(l_0 + l_1 + l_4 + ... + l_8) + 6*(l_2 + l_3) and
thus
l_2 + l_3 + d_3 <= 8/3*(l_0 + ... + l_8) + 3*(l_2 + l3)
<= 3*(l_0 + l_1 + ... + l_8) (No subscript omitted).
Using Deans notation, this means e <= 3*d.
On the other hand we can forget about part of the lefthand side and
get
5*(l_2 + l_3) <= 8*(d_0 + d_1 + d_2 + d_4 + ... + d_8) + 3*d_d_3
that is
5*(l_2 + l_3 + d_3) <= 8*(d_0 + ... + d_8). In Dean's notation, this
is
5*e <= 8*(1-d).
While equality in the first case can easily be achieved, this is not
so for the second case. This is because the proof uses only the fact
that the edge degree of the underlying graph is 8. Then our problem
can be restated as a problem of coloring graphs. one can easily
construct an infinite graph, that has edge degree 8 and admits a
coloring such that equality in the second case is reached. Thus no
improvement can be made by this 'local' method.
To prove Dean's conjecture, one has to take into account 'global'
effects.

Has anyone the right idea where to begin with that?

Hartmut
And a little later with a slightly confusing switch of notation:
-4426 From: Hartmut Holzwart
Date: Fri, 11 Sep 92 17:59:22 +0200
Subject: Infinite p2 with density 1/2


To John: The argument is really simple. Dean had an inequality that
can be written 8d_i+5d_(i+1)<=8, where d_i is the density of the i-th
generation. Adding up all these inequalities and using d_(n+1)=d_1 (typo corrected) for
period n things gives 13*(d_1+...+d_n)<=8*n and this is the result. Do
you see any flaw in that argument?

Hartmut
I hope I cited everything correctly. The second mail was an answer on a question by JHC...

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Re: Can we substantiate this claim?

Post by Book » July 8th, 2022, 6:08 pm

...that Crinkly heptomino was discovered in 1970? (and anything else noteworthy about this pattern?)

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Re: Can we substantiate this claim?

Post by hotdogPi » July 8th, 2022, 9:08 pm

Book wrote:
July 8th, 2022, 6:08 pm
...that Crinkly heptomino was discovered in 1970? (and anything else noteworthy about this pattern?)
All 108 heptominoes were either analyzed in 1970 or classified as "unknown so far" in Lifeline Volume 1.
User:HotdogPi/My discoveries

Periods discovered: 5-16,⑱,⑳G,㉑G,㉒㉔㉕,㉗-㉛,㉜SG,㉟,㊱,㊳S,㊵㊷㊹㊺㊽㊿,54G,55G,56,57G,60,62-66,70,72,74S,75,76S,80,84,90,96,100,102S,108,110,112,114G,116,117G,120,126G,128,138,147,154,156,180,196S,217,486,576

S: SKOP
G: gun

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Re: Can we substantiate this claim?

Post by Book » July 13th, 2022, 7:46 pm

"It has been proven that signals traveling non-destructively with the grain through zebra stripes cannot travel at less than the speed of light." (With the grain)

1. Is this proven by CGOLM&C Theorem 4.2?
2. Does this also mean they must travel at c?

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Re: Can we substantiate this claim?

Post by dvgrn » July 13th, 2022, 8:17 pm

Book wrote:
July 13th, 2022, 7:46 pm
"It has been proven that signals traveling non-destructively with the grain through zebra stripes cannot travel at less than the speed of light." (With the grain)

1. Is this proven by CGOLM&C Theorem 4.2?
2. Does this also mean they must travel at c?
Yes and yes. The form of the statement in the book is maybe a little bit clearer and more specific: "Every finite signal that moves [in a parallel direction] through a zebra stripes wire travels at a speed of c."

Signals definitely can't travel faster than c, by the definition of the speed of light, so the two forms of the statement are logically equivalent. "Finite signal", meaning "signal that consists of a finite length N of moving disturbance through the background pattern" is equivalent to the "traveling non-destructively" phrasing in the LifeWiki quotation.

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Re: Can we substantiate this claim?

Post by Book » July 17th, 2022, 6:57 pm

From Teeth:
This (and a related 65-cell pattern that Gotts found at about the same time) beat the record previously held by mosquito 5...


1. Would be nice to have a ref other than Lexicon for the March 2000 discovery of Teeth
2. Ditto the "related 65-cell pattern"--and an RLE we could preserve for this phantom would be great

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Re: Can we substantiate this claim?

Post by dvgrn » July 18th, 2022, 3:56 pm

Book wrote:
July 17th, 2022, 6:57 pm
From Teeth:
This (and a related 65-cell pattern that Gotts found at about the same time) beat the record previously held by mosquito 5...

1. Would be nice to have a ref other than Lexicon for the March 2000 discovery of Teeth
2. Ditto the "related 65-cell pattern"--and an RLE we could preserve for this phantom would be great
Here's the relevant LifeCA email, with LifeViewer code blocks added:
On Tue Mar 28, 2000 11:14am, Nick Gotts wrote: Subject: 65-cell patterns with quadratic growth

I like Dean's new kind of crystal growth!

This message reports an improvement on the minimum size pattern (in terms of number of cells) required to generate quadratic growth, and some associated investigations.

Some on the list will remember my first attempt in this direction, the `jaws' pattern, which used eight pairs of switch engines to generate a growing row of further switch engines. Some of the pairs were the `Noah's ark' pattern discovered around 1971 by (I think) Charles Corderman, others were a similar pair I found. I'll call patterns of this type, where two bare switch engines stabilise each other, `arks'. (I've found quite a few of these, all starting from 16 cells, but as I haven't been systematic about this, won't post them until I get round to a systematic search, unless anyone specifically wants them --- in which case it might take me a bit of time to collect them together.) Jaws initially had 150 cells, cut to 130 after Paul Callahan found some previously unknown 8- and 9-cell predecessors of the bare switch engine. Paul also found numerous ways of generating stabilised switch engines from small patches of cells, and from these I developed some four-glider collisions which produce infinite (linear) growth by constructing a single, stabilised switch engine. One of these:

Code: Select all

x = 151, y = 67, rule = B3/S23
bo$2bo$3o25$48bobo$49b2o$49bo32$150bo$148b2o$149b2o$141bo$142bo$140b3o!
has three gliders coming from one direction and the fourth at right angles to it, suggesting the possibility that four glider-wave producing arks might be able to produce a line of switch engines. However, the switch engines produced would travel back in the direction three of the gliders came from, and so would run into one of the arks. It was only quite recently I realised this would not necessarily prevent quadratic growth.

The following patterns all use one of two closely related four-glider collisions, different from the one above. (I've found a few others, but again have not been very systematic, apart from a subclass described at the end of this message.)

This is the first definite 65-cell quadratic growth pattern found, ousting the previous record holder, the 71-cell `mosquito 5':

Code: Select all

x = 646, y = 127, rule = B3/S23
640b3o$641bobbo$645bo$642bobo22$612bo$612boo$612bobbo$$613bobo$614bo5$
241boo$240bo$240bo$236b4o8$252boo$253bo$253boo$253bo$$250b3o45$3b3o$bo
bbo$o$bobo$438b3o$439bobbo$443bo$440bobo14$413boo$415bo$415bo$416b4o$
33bo$32boo$30bobbo$$30bobo$31bo!
This is the 65-cell quadratic growth pattern with the smallest bounding box yet found, produced by pushing the left and right halves of the pattern above 174 cells closer. I call this one `teeth':

Code: Select all

x = 472, y = 127, rule = B3/S23
466b3o$467bobbo$471bo$468bobo22$438bo$438boo$438bobbo$$439bobo$440bo5$
241boo$240bo$240bo$236b4o8$252boo$253bo$253boo$253bo$$250b3o45$3b3o$bo
bbo$o$bobo$264b3o$265bobbo$269bo$266bobo14$239boo$241bo$241bo$242b4o$
33bo$32boo$30bobbo$$30bobo$31bo!
The next three are not definitely quadratic growth patterns (my guess is that they all are quadratic, but their switch-engine production might eventually cease, or just possibly and more interestingly, slow down in such a way as to make them superlinear but subquadratic). The first is produced by pushing the left and right halves of the first pattern above 170 cells closer: in this case, when each constructed switch engine hits the nearest ark, it generates a glider which travels parallel to the ark, and collides with a glider that would otherwise help to produce a later switch engine. This leads to some of the expected teeth being absent:

Code: Select all

x = 476, y = 127, rule = B3/S23
470b3o$471bobbo$475bo$472bobo22$442bo$442boo$442bobbo$$443bobo$444bo5$
241boo$240bo$240bo$236b4o8$252boo$253bo$253boo$253bo$$250b3o45$3b3o$bo
bbo$o$bobo$268b3o$269bobbo$273bo$270bobo14$243boo$245bo$245bo$246b4o$
33bo$32boo$30bobbo$$30bobo$31bo!
All the above patterns produce block-laying switch engines. The remaining two, from a slightly different four-glider collision, produce glider-stream-switch engines. In both cases, the glider-streams interact in complicated ways with the arks. In both cases, also, different effects can be produced by shifting the left and right halves of the pattern relative to each other.

This one uses the same set of arks as the patterns above:

Code: Select all

x = 474, y = 129, rule = B3/S23
468b3o$469bobbo$473bo$470bobo22$440bo$440boo$440bobbo$$441bobo$442bo5$
241boo$240bo$240bo$236b4o8$252boo$253bo$253boo$253bo$$250b3o47$3b3o$bo
bbo$o$bobo$264b3o$265bobbo$269bo$266bobo14$239boo$241bo$241bo$242b4o$
33bo$32boo$30bobbo$$30bobo$31bo!
This one, actually the first of the five discovered, uses a slightly different set (which can't be used to produce the collision that makes a block-laying switch engine, so far as I can see):

Code: Select all

x = 764, y = 234, rule = B3/S23
3bo$3bo754b3o$boo756bobbo$o762bo$o759bobo$o$o6$30bo$29boo$27bobbo$$27b
obo$28bo9$730bo$730boo$730bobbo$$731bobo$732bo72$554b3o$555bobbo$559bo
$556bobo14$529boo$531bo$531bo$532b4o77$299bo3bo$300bobo$298bobbo$298bo
$298bo25$329bo$328b4o$326bo4bo$326bo$326bo!
The kind of feedback shown in the last three patterns can also be produced with just two arks (although I haven't found any quadratic growth patterns with fewer than four). The one below, found some time ago, produces an interesting sequence of subpatterns along its midline. Looking at the result after several hundred thou[s]and steps, at the samllest possible scale in Life32, a series of groups of birds-head-like shapes appears. Ignoring initial irregularities, the first group contains 3 heads, the second 4, the third 4, the fourth 3. As far as I was able to trace it (the program crashed), and with parentheses added for clarity, the sequence is:

((3 4 4 3)(4 3 4 3)(3 4 4 3)(3 4 4 3))
((3 4 4 3)(4 3 4 3)(3 4 4 3)(4 3 4 3))
((3 4 4 3)(4 3 4 3)(3 4 4 3)(3 4 4 3))
((3 4 4 3)(4 3 4 3)(3 4 4 3)(3 4 4 ?))

Assuming the last group is of 3, this sequence appears to have interesting self-similarities, very like the Morse-Thue sequence. Changing the vertical distance between the two arks gives different, often far more complicated results.

Returning to the four-ark quadratic growth patterns, you'd think there would be a 64-cell one, but so far I haven't found one. I'm currently working with an infinite class of four-glider collisions that produce stabilised switch engines, of which the following is an example:

Code: Select all

x = 195, y = 112, rule = B3/S23
bbo$obo$boo17$65bo$66bo$64b3o84$193bo$192bo$192b3o$$184bo$185bo$183b3o!
Like all the four-glider infinite growth collisions I know of, this uses what I call the "gliding down Herschel's throat" construction (if you run one, you'll see why I call it that), but in the pattern above, the first two gliders collide to form a pi which completes its development, so the remaining pair can be delayed as long as desired. I think this is the only such infinite class of four-glider collisions in which all the gliders come from two perpendicular directions (there are others in which the gliders that produce the pi come from two opposite directions, and these may or may not include the direction from which the remaining gliders come).

By the way, has anyone ever done a complete survey of three-glider collisions? From the recent discovery of the three glider -> pentadecathlon reaction, I'd guess not. There's an infinite number of them, but the ones where the third glider doesn't arrive until the first two have finished reacting should surely fall into a finite number of classes whose members differ only in timing, and in some cases the spacing of final objects.

Nick

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Re: Can we substantiate this claim?

Post by GUYTU6J » August 1st, 2022, 11:29 pm

This edit seems to imply that the Cordership-detecting reaction is a pseudo Heisenburp, but the main article on Model D Heisenburp does not mention the word "pseudo". Despite the somewhat complex interaction, this particular mechanism does not restore the passing spaceship by rebuilding it after destruction; so does it count as a pseudo Heisenburp?
Why do most 2-state OCA rules tend to get a diminishing span of interest and go into oblivion, like lost civilizations leaving little records for their beauty and power?

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Re: Can we substantiate this claim?

Post by pzq_alex » August 3rd, 2022, 7:49 am

GUYTU6J wrote:
August 1st, 2022, 11:29 pm
This edit seems to imply that the Cordership-detecting reaction is a pseudo Heisenburp, but the main article on Model D Heisenburp does not mention the word "pseudo". Despite the somewhat complex interaction, this particular mechanism does not restore the passing spaceship by rebuilding it after destruction; so does it count as a pseudo Heisenburp?
iirc the definition of a pseudo-Heisenburp is a Heisenburp that temporarily affects the passing spaceship, rather than rebuilding it after destruction.
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Stop turning this forum into a place for politics. Please.

Code: Select all

x=4,y=3,rule=B3S2-i3-a4ciz5j6c8
bo$3o$ob2o!

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Re: Can we substantiate this claim?

Post by dvgrn » August 4th, 2022, 6:34 am

pzq_alex wrote:
August 3rd, 2022, 7:49 am
GUYTU6J wrote:
August 1st, 2022, 11:29 pm
This edit seems to imply that the Cordership-detecting reaction is a pseudo Heisenburp, but the main article on Model D Heisenburp does not mention the word "pseudo". Despite the somewhat complex interaction, this particular mechanism does not restore the passing spaceship by rebuilding it after destruction; so does it count as a pseudo Heisenburp?
iirc the definition of a pseudo-Heisenburp is a Heisenburp that temporarily affects the passing spaceship, rather than rebuilding it after destruction.
Yeah, I think the "pseudo" distinction is a little bit awkward and unclear for some passing-spaceship detection interactions, or at least for some possible interactions.

There's some clarification in the Heisenburp and stable pseudo-Heisenburp articles. The original distinction between "pseudo" and "pure" Heisenburp reactions was for periodic detection mechanisms for gliders, where it was possible to retain a boundary of OFF cells all the way around the glider at all times, and still detect it. That "pure Heisenburp" kind of detection is not possible with a stable detection mechanism, as a rule, so that makes the Model D Heisenburp a "pseudo" reaction, pretty much by definition.

On the other hand, the Model D reaction is as close to "not even temporarily affecting" the passing Cordership as it's possible to get. All the cells that would normally be ON in the Cordership remain ON during the triggering of the detection mechanism (during two different points where the Cordership is adjacent to something). And I think you can even draw a one-cell-thick border of OFF cells around every phase of the Cordership, and there's no phase where an ON cell in the detection mechanism overlaps that border.

So the Model D Heisenburp seems to me to be a "just barely pseudo" or "technically pseudo" or "absolute-minimally pseudo" Heisenburp reaction, to the point where it doesn't really seem worth mentioning the word "pseudo" in the context of the Model D.

The big distinction is that in a stable pseudo Heisenburp for gliders, there's no way to detect a glider without destroying and rebuilding it, or at least seriously affecting it -- so you can say "pseudo" without thinking about what exactly "pseudo" means. But the same is not necessarily true for spaceships that produce detectable side sparks.

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Re: Can we substantiate this claim?

Post by GUYTU6J » August 5th, 2022, 11:30 pm

To make it a bit more confusing, there is also the term "out of the blue" for "a second spaceship created during a Heisenburp reaction". The article about maximum volatility gun says
...[it is] using many copies of Karel's p177 to generate gliders via pairs of passing spaceships in an out of the blue reaction.
Is it to be rephrased to "in a Heisenburp reaction" or "in a pseudo-Heisenburp reaction"?

---

EDIT: whoops, there is a major flaw in my original question: there are two bait reactions, not one, used on Corderships! The one in Model D is a beehive plus BFx59H, which shows a vital secondary interaction at generation 132:

Code: Select all

x = 94, y = 66, rule = LifeSuper
68.I$67.I.I2$67.I2.I$69.2I$70.I$84.2I$84.2I3$67.2I$69.I$68.2I$67.3I
15.I$67.2I16.2I5.2I$66.3I.I14.2I5.2I$67.I3.I10.2I$69.I2.I10.I$69.3I
12.I$70.2I3$78.2I2.2I$61.I15.3I2.I$3.2A56.I16.2I2.I$3.A57.I16.2I.2I$
4.A57.2I16.I4.I$3.2A57.3I20.2I$62.2I20.I.I2$38.I$37.I.I2$2A35.I2.I20.
I$2A37.2I21.I$15.2A23.I20.I$14.A2.A36.2I$15.2A37.2I2$60.I$37.2I20.3I$
39.I18.2I2.I$38.2I17.2I$37.3I15.3I$37.2I16.2I$36.3I.I14.2I$37.I3.I11.
I.I$39.I2.I11.2I$39.3I14.I$40.2I12.I2.I$57.I$54.3I2$52.I$50.I.I$52.I$
42.2I5.I.I$42.2I5.I$49.I.I$50.2I5$50.2I$50.2I!
The other found in 2012 and used here and here is a loaf plus two blocks:

Code: Select all

x = 85, y = 66, rule = LifeSuper
59.I$58.I.I2$58.I2.I$60.2I$61.I$75.2I$75.2I3$58.2I$60.I$59.2I$58.3I
15.I$58.2I16.2I5.2I$57.3I.I14.2I5.2I$58.I3.I10.2I$60.I2.I10.I$60.3I
12.I$61.2I3$69.2I2.2I$52.I15.3I2.I$52.I16.2I2.I$52.I16.2I.2I$53.2I16.
I4.I$53.3I20.2I$53.2I20.I.I2$29.I$28.I.I2$28.I2.I20.I$30.2I21.I$31.I
20.I$45.2I$45.2I2$10.2A39.I$2A7.A2.A15.2I20.3I$2A7.A.A18.I18.2I2.I$
10.A18.2I17.2I$28.3I15.3I$28.2I16.2I$27.3I.I14.2I$28.I3.I11.I.I$30.I
2.I11.2I$12.2A16.3I14.I$12.2A17.2I12.I2.I$48.I$45.3I2$43.I$41.I.I$43.
I$33.2I5.I.I$33.2I5.I$40.I.I$41.2I5$41.2I$41.2I!
And the edit I questioned above is concerned about the latter, not the former.
...
If the former in Model D is an "absolute-minimally pseudo" Heisenburp, then why is the latter a pseudo one?
Why do most 2-state OCA rules tend to get a diminishing span of interest and go into oblivion, like lost civilizations leaving little records for their beauty and power?

Here multiflorate splendour blooms forlorn
Midst broken fountains, mouldering walls.

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Re: Can we substantiate this claim?

Post by dvgrn » August 6th, 2022, 11:12 pm

dvgrn wrote:That "pure Heisenburp" kind of detection is not possible with a stable detection mechanism, as a rule, so that makes the Model D Heisenburp a "pseudo" reaction, pretty much by definition.
GUYTU6J wrote:
August 5th, 2022, 11:30 pm
... the edit I questioned above is concerned about the latter, not the former.
...
If the former in Model D is an "absolute-minimally pseudo" Heisenburp, then why is the latter a pseudo one?
Looking all of this over again, I think I should retract the sentence quoted above. It should be something like
dvgrn should have wrote:That "pure Heisenburp" kind of detection is not possible for gliders with a stable detection mechanism, so that makes any stable glider Heisenburp a "pseudo" reaction, pretty much by definition.
I think both of the Cordership detection reactions should not really be labeled as "pseudo", because every phase of the passing Cordership can be surrounded by a ring of orthogonally-connected OFF cells that don't overlap any of the live cells of the Heisenburp mechanism. That's still true even of the secondary reaction in the Model D.

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Re: Can we substantiate this claim?

Post by Book » August 11th, 2022, 1:32 pm

On the apgcode page, in the encoding objects-suffix section, there is the following curious statement regarding y1:
What the fourth value corresponds to is currently not known; it appears to be a hashing function.
Is this truly unknown? How would it becomes known?

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Re: Can we substantiate this claim?

Post by dani » August 11th, 2022, 4:41 pm

I'm pretty sure the fourth number is a hash value based on the population change between generations. This is how it's the same each time even if it appears on a different generation.
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Re: Can we substantiate this claim?

Post by Book » August 11th, 2022, 4:55 pm

dani wrote:
August 11th, 2022, 4:41 pm
I'm pretty sure the fourth number is a hash value based on the population change between generations. This is how it's the same each time even if it appears on a different generation.
I think so. How do we get authoritative? Anyone know this definitively?

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Re: Can we substantiate this claim?

Post by Book » August 13th, 2022, 8:16 pm

In "did you know" #160 there is a link to the quadratic growth section of the infinite growth article https://conwaylife.com/wiki/Infinite_gr ... tic_growth.
... that it is possible to construct patterns that temporarily exhibit cubic growth?
However that article section does not mention cubic growth. So, can we substantiate the above?

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Re: Can we substantiate this claim?

Post by dvgrn » August 13th, 2022, 10:38 pm

Book wrote:
August 13th, 2022, 8:16 pm
In "did you know" #160 there is a link to the quadratic growth section of the infinite growth article https://conwaylife.com/wiki/Infinite_gr ... tic_growth.
... that it is possible to construct patterns that temporarily exhibit cubic growth?
However that article section does not mention cubic growth. So, can we substantiate the above?
I was thinking that that article _used_ to say something about cubic growth... I didn't find it last time I hunted through the history a few weeks ago, but maybe my search wasn't exhaustive.

Anyway, a search for "cubic" on the forums certainly turns up lots of answers to "basic questions" of one sort or another, explaining why cubic growth is impossible in standard 2D CAs. I'm not immediately finding one source that's more authoritative than others, though. The topic doesn't get covered in a theorem in the Life textbook, or anything like that.

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Re: Can we substantiate this claim?

Post by Book » August 18th, 2022, 6:06 pm

Snarkmaker article says 2428 gliders; Book (B.2) says 2427. Truth?

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Re: Can we substantiate this claim?

Post by dvgrn » August 18th, 2022, 6:27 pm

Book wrote:
August 18th, 2022, 6:06 pm
Snarkmaker article says 2428 gliders; Book (B.2) says 2427. Truth?
Both of the actual statements are true. The Snarkmaker article includes

"1 glider (suppressed by a single cell) showing where a second Snarkmaker recipe could be safely appended".

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