Package sagbi/SB.IsInSA SAGBI
|This article is about a function from ApCoCoA-2.|
This function tests whether a polynomial is in a given standard-graded subalgebra.
SB.IsInSA(f: RINGELEM,S: TAGGED("$apcocoa/sagbi.Subalgebra")): BOOL
This function takes a polynomial f and a subalgebra S and tests whether f is an element of S using truncated SAGBI bases.
@param f A polynomial
@param S A standard-graded subalgebra, i.e. of type TAGGED("$apcocoa/sagbi.Subalgebra") and the generators of f are homogeneous polynomials with respect to the standard grading.
@return true if f is an element of S and false if not.
Use R ::= QQ[x,y,z]; S := SB.Subalgebra(R,[x^2,y+z]); f := x^4 +2*x^3*y +x^2*y^2 +x^2 +2*x*y +y^2; SB.IsInSA_SAGBI(f,S); -- true