https://en.wikipedia.org/wiki/Proof-of-stake
Maybe there's a better or more up-to-date introduction elsewhere.
Most bitcoin heavyweights who have researched proof of stake have concluded that it's not viable, and not worth further research in the context to trustless and decentralized systems.
Most bitcoin heavyweights who have researched proof of stake have concluded that it's not viable, and not worth further research in the context to trustless and decentralized systems.