Extensional constraint

Constraints on a set of variables $LaTeX: X =\{x_1, \dots, x_n\}$ can be stated in an extensional fashion by specifying a table that summarizes all allowed (or in an alternative formulation, all disallowed) combinations of assignments to the variables in $LaTeX: X$.
For instance, the extensional constraint $LaTeX: table(\{x,y\},\{[1,2],[1,3],[2,3]\})$ expresses the intensional constraint $LaTeX: x < y$ where $LaTeX: x$ and $LaTeX: y$ can take values $LaTeX: \{1,2,3\}$.