Talk:Reversible cellular automaton

Undecidability
This part of the lede is ambiguous:

"However, for cellular automata that are not defined by these methods [block or second-order], on arrays of two or more dimensions, testing reversibility is undecidable."

I understand that reversibility testing is undecidable in general, but does this also mean that there cannot exist a third method of constructing reversible automata? Q VVERTYVS (hm?) 08:48, 1 September 2015 (UTC)
 * I hope this edit makes it both clearer and a little more accurate. —David Eppstein (talk) 01:47, 27 September 2015 (UTC)

I don't see the GA symbol on the article page. Did I do something wrong? Edwininlondon (talk) 06:40, 2 October 2015 (UTC)
 * According to the instructions the symbol is supposed to be added later by a bot. But it also says you should add this article to Good articles/Mathematics and I don't know whether the bot is triggered by the GA template at the top of this article or by that addition. —David Eppstein (talk) 07:11, 2 October 2015 (UTC)