Nef polygon

The objects are named after the Swiss mathematician Walter Nef (1919–2013),[1] who introduced them in his 1978 book on polyhedra.

[4] In addition, the class of Nef polyhedra is closed with respect to the topological operations of taking closure, interior, exterior, and boundary.

However the class of Nef polyhedra is also closed with respect to the operation of regularization.

[6] In the language of Nef polyhedra you can refer to various objects as 'faces' with different dimensions.

[7] The Computational Geometry Algorithms Library, or CGAL, represents Nef Polyhedra by using two main data structures.