2 comments

  • linolevan7 hours ago
    This is a cool subcommunity! Had no idea there were still open problems that people were working on. Surprised to see human intuition is still around – would have expected a solution through pure brute force.
    • teraflop7 hours ago
      In that respect, it reminds me a bit of the busy beaver problem.<p>I wonder: consider the decision problem of determining whether or not a given still life is glider-constructible. Is this problem known to be undecidable?<p>It&#x27;s straightforward to show that an &quot;inverse&quot; of this problem -- given an arbitrary glider construction sequence, does it result in a still life? -- is undecidable, because gliders can construct patterns that behave like arbitrary Turing machines.
      • LegionMammal9786 hours ago
        My understanding is that the only still-lifes known <i>not</i> to have a glider synthesis are those containing the components listed at [0], which are &#x27;self-forcing&#x27; and have no possible predecessors other than themselves. Intuitively, one would think there must be other cases of unsynthesizable still-lifes (given that a still-life can have arbitrary internal complexity, whereas gliders can only access the surface), but that&#x27;s the only strategy we have to find them so far.<p>[0] <a href="https:&#x2F;&#x2F;conwaylife.com&#x2F;forums&#x2F;viewtopic.php?f=2&amp;t=6830&amp;p=201924" rel="nofollow">https:&#x2F;&#x2F;conwaylife.com&#x2F;forums&#x2F;viewtopic.php?f=2&amp;t=6830&amp;p=201...</a>
        • isoprophlex5 hours ago
          &gt; <i>Maybe it&#x27;s time to try pushing the envelope on this: what&#x27;s the biggest blobbiest most spacedustful period-4 c&#x2F;2 orthogonal spaceship that current technology can come up with? Might there be some kind of extensible greyship-like thing that escorts a patch of active agar instead of a stable central region, that might allow an easier proof of non-glider-constructibility?</i><p>I always enjoy the absolutely incomprehensible GoL jargon
      • vintermann4 hours ago
        Is it that easy though? Because the Turing machine constructions we have in the game of life are clearly not still lifes, and I don&#x27;t know if you can construct a Turing machine which freezes into a still life upon halting.
      • CraftingLinks6 hours ago
        Since GoL is Turing Complete,is such an inconstructable pattern an example of godels incompleteness theorem? I feel like I must be confusing some things here.
        • CraftingLinks5 hours ago
          Aah, but construction in GoL is not limited to gliders...still.
  • amelius2 hours ago
    It&#x27;s annoying here that you can&#x27;t run CGoL in reverse, like you can with the laws of physics.<p>Someone should invent a GoL (that is still interesting) with that property.
    • GaryHak1 hour ago
      Ever since programming GOL in assembly on Z80 i dreamt of this.<p>Game for two persons. The game runs, you can go back in time and modify by introducing gliders. Only problem is, how to turn it into a real game, what is the object. Maybe split the world in two and try building a stable configuration. The opponenent can launch the glider towards your turf, or something like that.