Sparse Merkle Trees
Sparse Merkle trees are a specialized type of Merkle tree where the vast majority of leaves are empty, allowing for efficient representation of very large data sets. In blockchain systems, they are often used to track the state of millions of accounts or positions without needing to store every single entry on-chain.
By using a sparse structure, the tree can be updated and queried with logarithmic complexity, which is essential for performance. They are particularly useful in rollup designs where the state must be proven to the main chain.
The efficiency of these trees is a critical factor in the scalability of decentralized derivatives, as they allow for the rapid validation of large numbers of margin accounts. Understanding their structure is key to building high-performance decentralized systems.