One proposal for plasma cash with coin splitting and merging

[danrobinson]

Why is it necessary that only adjacent coins merge? What do you think of Plasma Cash: Plasma with much less per-user data checking - #53 by danrobinson?

@ldct

The root plasma contract stores the subset of minimal coins that have been deposited, and no valid transaction can change this subset. if an invalid transaction with id X is committed, every honest coinholder that holds a coin Y that intersects X knows and immediately exits Y.

Quibble: in Plasma Cash, you don’t have to watch for invalid transactions and exit if you see one. You can just lazily wait for any exit attempt for any coin that intersects with yours, and challenge it then.