The simplicial complex defined by Wikipedia does not intersect itself and the winding number is thereby either 0 or 1. Our complexes may intersect themselves, or at least their embedding in the Euclidean space will and the winding number may be any integer.
The Wikipedia definition of simplicial complex would seem to say that two simplexes spanning the same set of points (in some Euclidean space) are identical. This identification stems indirectly from the definition of ‘simplex’.
The discrimination I need may be natural to algebraic topology but not to the geometrical simplex concept.
I suspect that chain complexes may have to do with this but the definitions there seem circular.
The Abstract simplicial complex seems to be just what we need.
It is a complex outside any particular Euclidean space.
I think the axiom is better written:
∀X (X∊K ➞ ∀Y (Y⊂X ➞ Y∊K))
This axiom seems to ignore orientation issues.
The mechanisms I use in my code deal with orientation in an abstract simplicial complex.