Now we could give the definition of hetero numbers.
Hetero numbers HN are defined as …, HN := …
with addition defined by [Cone A]R + [Cone B]R := …
Recall that …
Shown below are some examples.
In the left example, there is no “Boundary” triangle and the equivalent class of the cone is a hetero number.
In the middle example, there are two “Boundary” triangles (colored yellow) and the equivalent class of the cone is not a hetero number.
In the right example, there is no “Boundary” triangle and the equivalent class of the cone is a hetero number.