# I Vector Spaces Question

1. Feb 1, 2017

### Austin Chang

In a vector space can you limit the scalar. For example, if I have Vector space in ℤ2 can i only multiple integer scalars?

2. Feb 1, 2017

### Staff: Mentor

In this case it is called a $\mathbb{Z}-$module, i.e. the scalars are from a ring, in your example $\mathbb{Z}$. Vector spaces are required to have a field as scalar domain, that is we have invertible elements as scalars (and of course $0$). However, the field doesn't have to be "unlimited". E.g. $\{0,1\}$ is also a field.

3. Feb 1, 2017

### lavinia

You can limit the scalars to a subfield of the field of scalars but then you have a different vector space. For instance the real line is a one dimensional vector space over the field of real numbers. If you limit the scalars to the field of rational numbers, then the real line is an infinite dimensional vector space over the field of rational numbers.