HH^ZZ Module -- local cohomology

HH^ZZ Module -- local cohomology

Synopsis:

Function: cohomology -- general cohomology functor

Input:

an instance of class ZZ.

an instance of class Module.

Output:

an instance of class Module.

Optional arguments :

cohomology(..., Degree)

HH^i(M) -- computes the i-th local cohomology of M with respect to the maximal ideal generated by the variables of the ring.

i1 : R = QQ[x,y];

i2 : HH^2 (R^{-3})



o2 = cokernel | 0 -y x |

              | y x  0 |



                            2

o2 : R-module, quotient of R

i3 : HH^2 (R^{-4})



o3 = cokernel | 0 0  -y x |

              | 0 -y x  0 |

              | y x  0  0 |



                            3

o3 : R-module, quotient of R