Singular Manual: Delta

| #### D.5.15.11 Delta Procedure from library `resolve.lib` (see resolve_lib). Usage: Delta (BO); BO = basic object, a list: ideal W, ideal J, intvec b, list Ex, ideal ab, intvec v, intvec w, matrix M Assume: R = basering, a polynomial ring, W an ideal of R, J = ideal containing W Compute: Delta-operator applied to J in the notation of [Bravo,Encinas,Villamayor] Return: ideal Example:
    LIB "resolve.lib";
    ring R=0,(x,y,z),dp;
    ideal W=z^2-x;
    ideal J=x*y^2+x^3;
    intvec b=1;
    list E;
    ideal abb=maxideal(1);
    intvec v;
    intvec w=-1;
    matrix M;
    list BO=W,J,b,E,abb,v,w,M;
    Delta(BO);
    ==> _[1]=z2-x
    ==> _[2]=xy
    ==> _[3]=3x2z+y2z
    ==> _[4]=x3

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