Definition:Divisor (Algebra)/Notation

Definition
The conventional notation for $x$ is a divisor of $y$ is "$x \mid y$", but there is a growing trend to follow the notation "$x \mathrel \backslash y$", as espoused by etc.

From :
 * The notation '$m \mid n$' is actually much more common than '$m \mathrel \backslash n$' in current mathematics literature. But vertical lines are overused -- for absolute values, set delimiters, conditional probabilities, etc. -- and backward slashes are underused. Moreover, '$m \mathrel \backslash n$' gives an impression that $m$ is the denominator of an implied ratio. So we shall boldly let our divisibility symbol lean leftward.

An unfortunate unwelcome side-effect of this notational convention is that to indicate non-divisibility, the conventional technique of implementing $/$ through the notation looks awkward with $\backslash$, so $\not \! \backslash$ is eschewed in favour of $\nmid$.