Singular Manual: Parameters

| ### A.1.5 Parameters Let us deform the ideal in Long coefficients by introducing a parameter t and compute over the ground field Q(t). We compute the dimension at the generic point, i.e., 434#434.(This gives the same result as for the deformed ideal above. Hence, the above small deformation was "generic".) For almost all 435#435this is the same as 436#436,where 437#437.
      ring Rt = (0,t),(x,y),lp;
      Rt;
    ==> // coefficients: QQ(t)
    ==> // number of vars : 2
    ==> //        block   1 : ordering lp
    ==> //                  : names    x y
    ==> //        block   2 : ordering C
      poly f = x5+y11+xy9+x3y9;
      ideal i = jacob(f);
      ideal j = i,i[1]*i[2]+t*x5y8;  // deformed ideal, parameter t
      vdim(std(j));
    ==> 40
      ring R=0,(x,y),lp;
      ideal i=imap(Rt,i);
      int a=random(1,30000);
      ideal j=i,i[1]*i[2]+a*x5y8;  // deformed ideal, fixed integer a
      vdim(std(j));
    ==> 40

User manual for Singular version 4.3.2, 2023, generated by texi2html.