MAST stands for Merkelized Abstract Syntax Trees and is a combination of two terms, "Merkle tree" and "abstract syntax trees." It is one of the technologies aimed at improving Bitcoin. MAST will increase the scalability of the platform and improve the privacy of its users by dividing the smart contracts into two parts according to the concepts mentioned above. MAST is a symbiosis of an abstract syntax tree (AST)—which will break a smart contract into parts—and a hash tree, or a Merkle tree. This will reduce the size of the data in a block and check the origin of these split parts of a smart contract on the example of any hash in the tree.
The technology was developed by the experts Russell O'Connor, Pieter Wuille from Blockstream, and researcher Peter Todd of Bitcoin Core. The MAST test version will probably be available at the end of the year.