docs: "Affine Algebras" vs "Polyhedral Cones"

[micjoswig]

There are mathematical objects which occur in several corner stones in natural ways, which are largely independent though.

A first example of this kind are affine algebras, which are (rightfully) part of the commutative algebra documentation. In polyhedral terms these are polyhedral cones with a choice of a fixed lattice. This needs to be reflected in the documentation.

One choice (suggestion by Tommy) would be to create explicit conversion functions / constructors and to put the documentation there, with mutual links.

[mohamed-barakat]

Is the affine algebra of a rational polyhedral cone the monomial subalgebra of the polynomial (or Laurent polynomial in the nonconvex case) ring linearly generated by the monomials corresponding to the included lattice points? If yes, then these are special affine algebras and do not exhaust the entire class.