ExtCoh -- computes Ext of two cohomological Cp-Mackey fuctors

Usage:

Ext(i,M,N)
Inputs:
- i, an integer,
- M, a C_p Mackey Functor,
- N, a C_p Mackey Functor,
Outputs:
- a C_p Mackey Functor, the $i$th cohomological Ext Cp-Mackey Functor of $M$ and $N$

Description

Given two cohomological Cp-Mackey functors $M$ and $N$, we can compute their $i$th Ext Mackey functor in cohomological Mackey functors.

i1 : N = cokernel(matrix({{3}}));

i2 : M = makeZeroOnUnderlyingMackeyFunctor (3,N);

i3 : prune ExtCoh(3,M,M)

o3 =                   Res : 0
     cokernel | 3 |  -----------> 0  -┐ Conj : 0
                    <-----------     <┘
                       Tr : 0

o3 : CpMackeyFunctor

Ways to use ExtCoh:

ExtCoh(ZZ,CpMackeyFunctor,CpMackeyFunctor)

For the programmer

The object ExtCoh is a method function.

The source of this document is in CpMackeyFunctors/Documentation/HomAlgDoc.m2:92:0.