Interesting ideas. I understand the high-level idea of using X and Z to bound Y. Questions: Can you clarify what it means to use empty hashes for non-membershi

Interesting ideas. I understand the high-level idea of using X and Z to bound Y. Questions: Can you clarify what it means to use empty hashes for non-membership proofs? / For the Merkle-Patricia Tree structure, if the branches are ordered, wouldn't it be possible to use bounding for non-membership proofs?