Unique sink orientation

In mathematics, a unique sink orientation is an orientation of the edges of a polytope such that, in every face of the polytope, there is exactly one vertex for which all adjoining edges are oriented inward. If a polytope is given together with a linear objective function, and edges are oriented from vertices with smaller objective function values to vertices with larger objective values, the result is a unique sink orientation. Thus, unique sink orientations can be used to model linear programs as well as certain nonlinear programs such as the smallest circle problem.

This keyword could refer to multiple things. Here are some suggestions: