next | previous | forward | backward | up | top | index | toc | Macaulay2 website
SRdeformations :: cokerElement

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

Synopsis

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

o3 = 0

o3 : cokernel | -1 -1 -1 |
              | 1  0  0  |
              | 0  1  0  |
              | 0  0  1  |
i4 : c2==(0_(class c2))

o4 = true
i5 : iszero c2

o5 = true

See also

Ways to use cokerElement :

For the programmer

The object cokerElement is a method function.