Subdual

Subdual is a term that appears sporadically in scholarly writing and does not have a single, widely accepted definition. In many contexts, it is used to describe a relation or object that is in some sense a subordinate or restricted version of a dual concept. The exact meaning is determined by the field and author.

In mathematics, some authors use subdual to refer to the dual object associated with a substructure, such as the dual of a subspace W of a vector space V. The set of linear functionals on W can be identified with a subspace of V*, which can be described informally as the subdual of W relative to V.

Similarly, in convex geometry or polyhedral theory, subdual may denote the dual of a subpolytope or the dual obtained after restricting a dual construction to a subcollection of faces.

In philosophy, subdual occasionally appears in discussions of dualities where one side is regarded as subordinate or derivative of the other, though this usage is not standardized.

Because subdual has no universal definition, readers should check the specific context and sources to determine its intended meaning. See also: duality, dual, subspace, subobject.