's logic
M9859 is part of Tamura's logic, which is a formal logic system proposed by Japanese logician Koji Tamura. It is a monadic first-order logic that allows for efficient reasoning about simple structures, such as directed graphs or trees. It can be used to represent and reason about finite-state systems, finite-state automata, and other problems that have a natural state-based structure. Unlike other logical systems, M9859 is designed to be used with the automated theorem prover Maude and its associated simplification system Maude-NPA. This means that it can be used to prove propositional and first-order logical properties, as well as higher order properties, such as modal logics.