Cross Chains - What's the Difference Between That and a Block Chain?

In a cross chain world, you're trying to trade a big coin for aneath. How do you do that in a dcentralized way? And i think the kee thing here is, the more it's not a black and white thing. An sthrt can't be her for most bostan worlds. What you count is what you'r goal is, and what you count as tralized there in the first place. I've never seen anyone really pull this off that well, but theoretically, you can do this with roll ups,. In so far as these are valid blocks, thenyou have serve this chalendge of etherian block chain history