In utility theory, the utility function of an agent is a function that ranks "all" pairs of consumption bundles by order of preference ("completeness") such that any set of three or more bundles forms a transitive relation. This means that for each bundle formula_46 there is a unique relation, formula_47, representing the utility (satisfaction) relation associated with formula_46. The relation formula_49 is called the utility function. The range of the function is a set of real numbers. The actual values of the function have no importance. Only the ranking of those values has content for the theory. More precisely, if formula_50, then the bundle formula_46 is described as at least as good as the bundle formula_52. If formula_53, the bundle formula_46 is described as strictly preferred to the bundle formula_52.