If $R=\{(n,k) \mid n,k\in \{1,2,3,4,5,6\}, n \mid k\}$ is a relation. What does the notation $n \mid k$ mean?

Question

Let $R=\{(n,k) \mid n,k\in \{1,2,3,4,5,6\}, n \mid k\}$ be a relation. What does the notation $n \mid k$ mean? I haven't seen this before, does this mean that $n$ is divisble by $k$?

Answer 1

Since you phrase it as "$n$ is divisible by $k$", I will put this is the same language:

"$n\mid k$" means $k$ is divisible by $n$.

But it's often read as "$n$ divides $k$".

It means that there is some integer $m$ such that $nm=k$.