- Operator: ++

i1 : R = ZZ/101[a..c]; |

i2 : image vars R ++ kernel vars R o2 = image {0} | a b c 0 0 0 | {1} | 0 0 0 -b 0 -c | {1} | 0 0 0 a -c 0 | {1} | 0 0 0 0 b a | 4 o2 : R-module, submodule of R |

The projection and inclusion maps for direct sums can be obtained with the following methods.

- Module ^ Array -- projection onto summand
- Module _ Array -- inclusion from summand

The components can be recovered later with components or with formation.

- directSum -- direct sum of modules or maps