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CoherentSheaf / CoherentSheaf -- quotient of coherent sheaves

Synopsis

Description

We compute the cohomology of two sheaves supported on an elliptic curve.
i1 : X = Proj(QQ[x,y,z])

o1 = X

o1 : ProjectiveVariety
i2 : I = ideal(y^2*z-x*(x-z)*(x-11*z))

              3      2     2         2
o2 = ideal(- x  + 12x z + y z - 11x*z )

o2 : Ideal of QQ[x..z]
i3 : N = (sheaf module I)/(sheaf module I^2)

o3 = subquotient (| -x3+12x2z+y2z-11xz2 |, | x6-24x5z-2x3y2z+166x4z2+24x2y2z2+y4z2-264x3z3-22xy2z3+121x2z4 |)

                                            1
o3 : coherent sheaf on X, subquotient of OO
                                           X
i4 : G = OO_X^1/I

o4 = cokernel | -x3+12x2z+y2z-11xz2 |

                                         1
o4 : coherent sheaf on X, quotient of OO
                                        X
i5 : HH^1(G)

       1
o5 = QQ

o5 : QQ-module, free
i6 : HH^1(N)

       9
o6 = QQ

o6 : QQ-module, free

See also

Ways to use this method: