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D.15.17.3 SPOLY

Procedure from library sagbigrob.lib (see sagbigrob_lib).

Usage:
SPOLY(I,A); I ideal of subalgebra A, A subalgebra (which is a finite sagbi basis).

Return:
an ideal S: S-polynomials of ideal I

Example:
 
LIB "sagbigrob.lib";
// Example 1:
ring r=ZZ,(x,y),Dp;
ideal A=2x2+xy,2y2,3xy;
ideal I=4x2y2+2xy3,18x2y4;
SPOLY(I,A);
==> _[1]=18xy5
==> _[2]=4x3y5+2x2y6
// Example 2:
ring r2=QQ,(x,y),Dp;
ideal A=x2,xy;
ideal I=x3y+x2,x4+x2y2,-x3y3-x2y2;
SPOLY(I,A);
==> _[1]=-x3y3+x4
==> _[2]=-x5y5+x6y2