Edge-Shifted Decision Diagrams for Multiple-Valued Logic

Symbolic data structures for multi-valued logics are useful in a number of applications, from model-checking to circuit design and switch-level circuit verification. Such data structures are referred to as decision diagrams, and are typically considered effective if they are small, i.e., common co-factors of a function are shared, and canonical, i.e., given a variable ordering, there is a unique decision diagram representing this function. In this paper we propose and evaluate a decision diagram variety, called Edge-Shifted Decision Diagrams (ESDDs). These diagrams are multi-valued, support structure sharing, and enjoy canonicity. We further list sufficient conditions to ensure canonicity of decision diagrams with unary edge transformers.