(Disclaimer: I hold Mina.) There is no need for Mina archival nodes to exist outside of running services like block explorers (which are admittedly nice to have

(Disclaimer: I hold Mina.) There is no need for Mina archival nodes to exist outside of running services like block explorers (which are admittedly nice to have). The Mina SNARK proof proves two properties at once: a) the state transitions from the previous block to this one are valid (they don't create money from thin air, etc.) and b) the previous block used in (a) itself carries a valid proof. The contents of previous blocks do not necessarily need to be kept at all, because of the "zero-knowledge" part of zero-knowledge proofs. Much like Yao's millionaires[1] don't have to reveal their net worths, the latest block's proof doesn't have to "reveal" the entire history that came before it. [1]: https://en.wikipedia.org/wiki/Yao%27s_Millionaires%27_Problem https://en.wikipedia.org/wiki/Yao%27s_Millionaires%27_Proble...