Constraint Processing

Preface

A constraint is a restriction on a space of possibilities; it is a piece of knowledge that narrows the scope of this space. Because constraints arise naturally in most areas of human endeavor, they are the most general means for formulating regularities that govern our computational, physical, biological, and social worlds. Some examples: the angles of a triangle must sum to 180 degrees; the four nucleotides that make up DNA strands can only combine in particular sequences; the sum of the currents flowing into a node must equal zero; Susan cannot be married to both John and Bill at the same time. Although observable in diverse disciplines, they all share one feature in common: they identify the impossible, narrow down the realm of possibilities, ...