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NmzEhrhartRing(L: LIST of RINGELEM, s: RINGELEM): LIST of RINGELEM
The exponent vectors of the given monomials are considered as vertices
of a lattice polytope
. The Ehrhart ring of a (lattice)
is the monoid algebra defined by the monoid of
lattice points in the cone over the polytope
; see the book
by Bruns and Gubeladze, Polytopes, Rings, and K-theory, publ.
Springer 2009, pp. 228--229.
The function returns the generators of the Ehrhart ring. It uses the
indeterminate in the second argument as auxiliary indeterminate of the
/**/ use R::=QQ[x,y,z,t];
[x^2*t, z^3*t, x*y*t, y^2*t]