Page "Constraint satisfaction problem" Paragraph 6

Formally, a constraint satisfaction problem is defined as a triple, where is a set of variables, is a domain of values, and is a set of constraints.

Every constraint is in turn a pair ( usually represented as a matrix ), where is an-tuple of variables and is an-ary relation on.

An evaluation of the variables is a function from the set of variables to the domain of values,.

An evaluation satisfies a constraint if.

A solution is an evaluation that satisfies all constraints.