What is the difference between proof of work, proof of action, and proof of authority?

Proof-of-work (PoW) is a consensus algorithm where nodes on a blockchain network provide evidence they have used computational power to achieve agreement about transactions. 

Proof-of-authority is another consensus algorithm where a limited number of trusted validator nodes validate the transactions. These trusted node owners are usually known entities with their reputations on the line for the right to validate blocks.

Proof-of-action (PoA) utilizes nodes to facilitate operation of an algorithmic protocol to identify contributions in the external world blockchain, such as contributing money to a reclamation project or participating in an Green digital property, and to correspondingly determine how GREEN reward is distributed among node operators through the Green Blockchain in recognition of such contributions.