Fundamental normal surface
= Fundamental normal surface
A fundamental <normal surface> has a nonzero admissible coordinate vector which is not the sum of two nonzero admissible vectors. Fixing the allowed quadrilateral type in every <tetrahedron> reduces the problem to the <Hilbert basis of a rational cone>. There are finitely many choices of quadrilateral types and finitely many indecomposable vectors for each choice.