A system selects a plurality of attributes common to objects being compared and defines at least one value space for each selected attribute. Each selected attribute can have a value space that is different from a value space of the same attribute associated with a different object. The system defines an ordering system for each value space including selecting whether the value space consists of non-ordered values, partially ordered values, or fully ordered values. An objective function is defined for each ordering system and the objective function maps a pair of values of a value space to a number value. The system normalizes each objective function and defines a mapping from the plurality of objective functions to a first general objective function.