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# cokerElement -- Gives an element in the cokernel of a matrix.

- Usage:
    `cokerElement(v,A)`
- Inputs:
  - v, a vector,
  - A, a matrix,
- Outputs:
  - a thing,

## Description

Gives the element in the cokernel of A represented by v. The Vector v has to lie in target of A.

    i1 : A= matrix {{-1, -1, -1}, {1, 0, 0}, {0, 1, 0}, {0, 0, 1}}

    o1 = | -1 -1 -1 |
         | 1  0  0  |
         | 0  1  0  |
         | 0  0  1  |

                  4       3
    o1 : Matrix ZZ  <-- ZZ

    i2 : c1=cokerElement(vector {1,1,0,0},A)

    o2 = | 2 |
         | 0 |
         | 0 |
         | 0 |

    o2 : Vector

    i3 : c2=cokerElement(vector {1,-1,0,0},A)

    o3 = 0

    o3 : Vector

    i4 : c2==(0_(class c2))

    o4 = true

    i5 : iszero c2

    o5 = true

## See also

- inducedMap -- compute an induced map

## Ways to use cokerElement:

- `cokerElement(Matrix,Matrix)`
- `cokerElement(Vector,Matrix)`

## For the programmer

The object cokerElement is a method function.

The source of this document is in /build/macaulay2-88fgJW/macaulay2-1.25.11+ds/M2/Macaulay2/packages/SRdeformations.m2:4034:0.