degeneracyLocus(ZZ,AbstractSheaf,AbstractSheaf)

Synopsis

Usage:
degeneracyLocus(k,B,A)
Function: degeneracyLocus
Inputs:
- k, an integer
- B, an abstract sheaf
- A, an abstract sheaf
Outputs:
- an abstract variety, the locus where the rank of a generic map from A to B is at most k

i1 : X = base(5, Bundle => (A,3,a), Bundle => (B,3,b))

o1 = X

o1 : an abstract variety of dimension 5

i2 : Z = degeneracyLocus(2,B,A)

o2 = Z

o2 : an abstract variety of dimension 4

i3 : Z/X

o3 = a variety map

o3 : a map to X from Z

i4 : (Z/X)_* 1

o4 = - a  + b
        1    1

o4 : QQ[a , a , a , b , b , b ]
         1   2   3   1   2   3