# Definition:Common Divisor/Integers

## Definition

Let $S$ be a finite set of integers, that is:

$S = \set {x_1, x_2, \ldots, x_n: \forall k \in \N^*_n: x_k \in \Z}$

Let $c \in \Z$ such that $c$ divides all the elements of $S$, that is:

$\forall x \in S: c \divides x$

Then $c$ is a common divisor (or common factor) of all the elements in $S$.

## Examples

### $20$, $70$ and $80$

The integers $20$, $70$ and $80$ have $2$, $5$ and $10$ as common divisors.