In https://eips.ethereum.org/EIPS/eip-4337, the authors say "Users send UserOperation objects into a separate mempool". i was wondering what it means.. and now, i think that they refer to off-chain memory pool for storing Pending UserOperation(High-level Transaction). so, i think that 'alt mempool' is probably 'alternative memory pool' that is implemented based distributed in-memory key-value store (e.g. Redis) that stores pending UserOperations.
Did I understand correctly? how do you think about it?
what i did : read and read and think.. about eip-4337. what i expect : check whether i understand it correctly or not