simplexissa
Simplexissa is a term that appears to be a misspelling or a less common variation of "simplex". A simplex is a fundamental concept in geometry and topology. In geometry, a simplex is the simplest possible polytope (a geometric object with flat sides) in any given dimension. For example, a 0-simplex is a point, a 1-simplex is a line segment, a 2-simplex is a triangle, and a 3-simplex is a tetrahedron. More generally, an n-simplex is the convex hull of n+1 affinely independent points in some Euclidean space.
In topology, a simplex is used as a building block for more complex spaces. The standard n-simplex