Varieties of constraints Unary constraints involve a single variable, ■e.g,SA+green Binary constraints involve pairs of variables, ▣e.g,SA+WA Higher-order constraints involve 3 or more variables, 4Feb2g,cryptarithretis olmssonsraints P4 Feb 2004 CS 3243 - Constraint Satisfaction 8 Varieties of constraints ◼ Unary constraints involve a single variable, ◼ e.g., SA ≠ green ◼ ◼ Binary constraints involve pairs of variables, ◼ e.g., SA ≠ WA ◼ ◼ Higher-order constraints involve 3 or more variables, ◼ e.g., cryptarithmetic column constraints ◼