1.109: Vector module
A vector module is the set of vectors spanned by a number n of basis vectors with integer coefficients. The basis vectors should be independent over the integers, which means that any linear combination
| ∑ | m i a i |
| i |
with m i integers is equal to zero if, and only if, all coefficients m i are zero. The term Z-module is sometimes used to underline the condition that the coefficients are integers. The number of basis vectors is the rank of the vector module.