Understanding "Divides" aka "|" as used logic What are the rules for using the divides operator aka "$\mid$"? Is it false to say $2\mid5$ since $5/2$ = $2.5$ and $2.5\notin\mathbb{Z}$? Or does my question imply a misunderstanding?
I am seeing this for the first time in the 6.042J, Lecture 2: Induction on MIT OCW.
Thanks for the help.

That's correct. We use the divide operator to denote the following:
We say for two integers $a$, $b$, that $a$ divides $b$ (or $a|b$) if $b = ka$ for some integer $k$. 
