overdefined

Overdefined is an adjective used to describe a system, model, specification, or definition that imposes more constraints or information than are necessary or feasible to satisfy. In such cases, the object is defined in a manner that restricts possibilities beyond what the context requires, which can lead to inconsistency, ambiguity, or infeasibility.

Although used in various disciplines, overdefined is less standardized than related terms. In mathematics and data analysis, more common terms are overdetermined or over-specified. When people use overdefined, they often intend one of these ideas: either the constraints exceed the degrees of freedom (overdetermined) or the specification imposes conflicting or redundant requirements (over-specified). The choice of term can depend on whether the emphasis is on equations and unknowns or on descriptive definitions.

Examples: In a linear system with more equations than unknowns, the system is typically overdetermined and may have no exact solution. In a data model, defining a field to be both the sum of two other fields and independently fixed to a constant would overdefine the field and create inconsistency unless reconciled. In software configuration, requiring a parameter to simultaneously satisfy two different computed values is another form of overdefinition.

See also: overdetermined, over-specified, underdefined.