Singular Manual: FultonA

| #### D.15.4.58 FultonA Procedure from library `chern.lib` (see chern_lib). Usage: FultonA(I); I an ideal Return: list of integers Purpose: computes the Fulton classes of the subscheme defined by I Note: Example:
    LIB "chern.lib";
    // Consider a 3-dimensional projective space
    ring r = 0, (x, y, z, w), dp;
    // Consider 3 non-coplanar lines trough one point and compute the Fulton class
    ideal I=xy, xz, yz;
    I;
    ==> I[1]=xy
    ==> I[2]=xz
    ==> I[3]=yz
    FultonA(I);
    ==> [1]:
    ==>    0
    ==> [2]:
    ==>    0
    ==> [3]:
    ==>    3
    ==> [4]:
    ==>    2
    // Now consider 3 coplanar lines trough one point and its Fulton class
    ideal J=w, x*y*(x+y);
    J;
    ==> J[1]=w
    ==> J[2]=x2y+xy2
    FultonA(J);
    ==> [1]:
    ==>    0
    ==> [2]:
    ==>    0
    ==> [3]:
    ==>    3
    ==> [4]:
    ==>    0

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