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Stabilizing the UWSS

Posted: April 20th, 2026, 1:21 pm
by roee.s
Hello all!
I recently made progress on a problem that bugged me for years: Stabilizing the underweight spaceship (i.e. the roteightor) as a c/2 spaceship.
Using a script that turns game of life problems into integer linear programming problems for the scip solver I found this partial spaceship:

Code: Select all

x = 13, y = 16, rule = B3/S23
2b3o3b2o$4bo2b2obo$4b2o4b2o$9b2o$4bob4o$3bob3o$6bo3b3o$bob2o4bo2bo$bo
3bo6bo$3b2o2bo3bo$2b2o3b2o$2b2ob4obo$3b2o2b2ob2o$2bob2o3b2o$ob2o2bob2o
$ob2o3bo!
So first I want to share my excitement with the world because this feels like quite some progress for me.
Second I want to ask if any of you who also might have been interested in the problem (or just want to help another CA enthusiast) might help me complete this (perhaps less a column or two) to a working spaceship, or advise me on how to do so myself. I saw that other people used llsss to search for spaceships and posted about partials before so I guess this is a direction but I saw it takes 14GB to compile which I don't currently have available (because of another scip instance and I prefer seeing if it could complete first) and the section about extending partials in the llsss tutorial isn't written yet anyway so I'll probably need some advice regardless.
Third, if people are interested in the way I converted game of life (and also highlife) search problems into ilp problems I'll be glad to answer your questions. I probably want to share the code with the world in the future but it's not really ready yet because I started from writing this stuff for highlife and there are some stuff I haven't really implemented for life yet, so if you think just uploading txt files with code to this forum when they're ready is a terrible idea and I should do something else this will also be good to read.
Thanks!

Re: Stabilizing the UWSS

Posted: April 20th, 2026, 7:25 pm
by Entity Valkyrie 2
roee.s wrote: April 20th, 2026, 1:21 pm Hello all!
I recently made progress on a problem that bugged me for years: Stabilizing the underweight spaceship (i.e. the roteightor) as a c/2 spaceship.
Using a script that turns game of life problems into integer linear programming problems for the scip solver I found this partial spaceship:

Code: Select all

x = 13, y = 16, rule = B3/S23
2b3o3b2o$4bo2b2obo$4b2o4b2o$9b2o$4bob4o$3bob3o$6bo3b3o$bob2o4bo2bo$bo
3bo6bo$3b2o2bo3bo$2b2o3b2o$2b2ob4obo$3b2o2b2ob2o$2bob2o3b2o$ob2o2bob2o
$ob2o3bo!
So first I want to share my excitement with the world because this feels like quite some progress for me.
Second I want to ask if any of you who also might have been interested in the problem (or just want to help another CA enthusiast) might help me complete this (perhaps less a column or two) to a working spaceship, or advise me on how to do so myself. I saw that other people used llsss to search for spaceships and posted about partials before so I guess this is a direction but I saw it takes 14GB to compile which I don't currently have available (because of another scip instance and I prefer seeing if it could complete first) and the section about extending partials in the llsss tutorial isn't written yet anyway so I'll probably need some advice regardless.
Third, if people are interested in the way I converted game of life (and also highlife) search problems into ilp problems I'll be glad to answer your questions. I probably want to share the code with the world in the future but it's not really ready yet because I started from writing this stuff for highlife and there are some stuff I haven't really implemented for life yet, so if you think just uploading txt files with code to this forum when they're ready is a terrible idea and I should do something else this will also be good to read.
Thanks!
This is known:

Code: Select all

x = 16, y = 18, rule = B3/S23
5b2o$4b3o4bo$4b2o2bo2b2o$2b3o2bobobobo$2b2o3bo5b2o$9bob3o$12bo$8b3o$b
5o7b3o$o5b3obobo2bo$9bo5bo$o7b3o3bo$2bo8bo$10bo2bo$2bob2o4bo2b2o$2bob
4ob2ob2o$7bo4bo$5b3o2b2o!

Re: Stabilizing the UWSS

Posted: April 21st, 2026, 12:42 am
by roee.s
Entity Valkyrie 2 wrote: April 20th, 2026, 7:25 pm This is known:

Code: Select all

x = 16, y = 18, rule = B3/S23
5b2o$4b3o4bo$4b2o2bo2b2o$2b3o2bobobobo$2b2o3bo5b2o$9bob3o$12bo$8b3o$b
5o7b3o$o5b3obobo2bo$9bo5bo$o7b3o3bo$2bo8bo$10bo2bo$2bob2o4bo2b2o$2bob
4ob2ob2o$7bo4bo$5b3o2b2o!
Wow! My bad. Who found it? Where is this documented? I want to put this in the wiki.

Re: Stabilizing the UWSS

Posted: April 23rd, 2026, 7:59 am
by hotcrystal0
roee.s wrote: April 21st, 2026, 12:42 am Wow! My bad. Who found it? Where is this documented? I want to put this in the wiki.
The earliest I can trace that is a post in 2020 by wwei:
wwei23 wrote: December 4th, 2020, 10:35 pm
Sokwe wrote: December 4th, 2020, 9:07 pm The spark on the right can support a small previously-known tagalong to create a new 90-cell ship:
That's just barely small enough to make it into my small 2c/5 ships collection.
Honest question here. Why make this big list of small ships? I don't get the point of listing every single combination of tagalongs. Just a list of freestanding ships, components, and tagalongs would do, wouldn't it?

Just for fun, I tried to complete the UWSS. This is what I came up with:

Code: Select all

x = 18, y = 16, rule = Immigration
8.3B$4.A3.B2.B2.A$3.3A2.B4.3A$2.A2.2A2.B5.2A$.3A.A6.A4.A$7.A.A.A.3A.A
$3.A.A.A2.2A3.A$2.A4.A.A.A$3.2A4.A5.3A$2A7.A5.A.A$3A5.A5.2A.A$.3A4.A
5.2A$3.2A3.A$3.2A3.A3.A.2A$8.A$9.A.A!

Re: Stabilizing the UWSS

Posted: April 27th, 2026, 9:32 am
by b-engine
I've done this exact thing before:
b-engine wrote: September 24th, 2024, 9:09 am (Revival)
Attempt to stabilize UWSS into a spaceship:

Code: Select all

x = 18, y = 16, rule = B3/S23
7b3o$3bo2bo2bo3bo$2b3o4bo2b3o$b2o5bo2b2o2bo$o4bo6bob3o$ob3obobobo$2bo
3b2o2bobobo$6bobobo4bo$3o5bo4b2o$obo5bo7b2o$ob2o5bo5b3o$2b2o5bo4b3o$9b
o3b2o$2b2obo3bo3b2o$9bo$6bobo!

Re: Stabilizing the UWSS

Posted: April 28th, 2026, 1:17 pm
by I6_I6
b-engine wrote: April 27th, 2026, 9:32 am I've done this exact thing before:
b-engine wrote: September 24th, 2024, 9:09 am (Revival)
Attempt to stabilize UWSS into a spaceship:

Code: Select all

x = 18, y = 16, rule = B3/S23
7b3o$3bo2bo2bo3bo$2b3o4bo2b3o$b2o5bo2b2o2bo$o4bo6bob3o$ob3obobobo$2bo
3b2o2bobobo$6bobobo4bo$3o5bo4b2o$obo5bo7b2o$ob2o5bo5b3o$2b2o5bo4b3o$9b
o3b2o$2b2obo3bo3b2o$9bo$6bobo!
There's another one in that same post:

Code: Select all

x = 24, y = 16, rule = B3/S23
b3o17b3o$o2bo16bo2bo$3bo7b3o9bo$3bo3bo2bo2bo3bobo3bo$obo3b3o4bo2b2o2b
obo$6b2o4bo2b2obo$6bob2o5bob3o$6bo3bo3b2o3bo$4b2o6bob2ob2o$5b2o5b2o2b
3o$5b3o2bobo3bo$7b2obo2bobo2bo$10bo5b2o$7b2o$7b2o6bobo$15bobo!