Description
The chain complex
C should be a direct sum, and the result is the map corresponding to inclusion from the sum of the components numbered or named
i, j, ..., k.
i1 : R = QQ[a,b];
|
i2 : C = res coker vars R
1 2 1
o2 = R <-- R <-- R <-- 0
0 1 2 3
o2 : ChainComplex
|
i3 : D = C ++ C
2 4 2
o3 = R <-- R <-- R <-- 0
0 1 2 3
o3 : ChainComplex
|
i4 : D_[0]
2 1
o4 = 0 : R <--------- R : 0
| 1 |
| 0 |
4 2
1 : R <--------------- R : 1
{1} | 1 0 |
{1} | 0 1 |
{1} | 0 0 |
{1} | 0 0 |
2 1
2 : R <------------- R : 2
{2} | 1 |
{2} | 0 |
3 : 0 <----- 0 : 3
0
o4 : ChainComplexMap
|
i5 : D_[1,0]
2 2
o5 = 0 : R <----------- R : 0
| 0 1 |
| 1 0 |
4 4
1 : R <------------------- R : 1
{1} | 0 0 1 0 |
{1} | 0 0 0 1 |
{1} | 1 0 0 0 |
{1} | 0 1 0 0 |
2 2
2 : R <--------------- R : 2
{2} | 0 1 |
{2} | 1 0 |
3 : 0 <----- 0 : 3
0
o5 : ChainComplexMap
|
If the components have been given names (see
directSum), use those instead.
i6 : D = (a=>C) ++ (b=>C)
2 4 2
o6 = R <-- R <-- R <-- 0
0 1 2 3
o6 : ChainComplex
|
i7 : D_[a]
2 1
o7 = 0 : R <--------- R : 0
| 1 |
| 0 |
4 2
1 : R <--------------- R : 1
{1} | 1 0 |
{1} | 0 1 |
{1} | 0 0 |
{1} | 0 0 |
2 1
2 : R <------------- R : 2
{2} | 1 |
{2} | 0 |
3 : 0 <----- 0 : 3
0
o7 : ChainComplexMap
|