|
|
D.15.1.1 arc
Procedure from library arc.lib (see arc_lib).
- Usage:
- arc(I, J); arc(I, J, optList); I: ideal defining the scheme, J: ideal defining the fat point, optList: list of integers (optional) indices of coefficients to skip
- Return:
- A ring containing the ideal arcideal in the variables of T.
Example:
| | LIB "arc.lib";
ring R = 0, (x,y), dp;
ideal I = x^4 + y^3;
ideal J = x^2,y^2; // fat point at origin
list L; // optional skips
def S = arc(I, J, L); // same as def S = arc(I,J);
setring S;
ideal A = arcideal;
S;
==> // coefficients: QQ considered as a field
==> // number of vars : 8
==> // block 1 : ordering dp
==> // : names a1 a2 a3 a4 a5 a6 a7 a8
==> // block 2 : ordering C
A;
==> A[1]=a1^4+a2^3
==> A[2]=4*a1^3*a3+3*a2^2*a4
==> A[3]=4*a1^3*a5+3*a2^2*a6
==> A[4]=12*a1^2*a3*a5+4*a1^3*a7+6*a2*a4*a6+3*a2^2*a8
|
|
