If $X$ is a topological space and $A$ is a (closed, usually) subset of $X$, then the quotient space obtained by "collapsing $A$ to a point" is often denoted by $X / A$.
Unfortunately, that notation conflicts with the standard notation $G/H$ for a quotient (topological) group in the case that $G$ is a (topological) group and $H$ is a normal subgroup.
For example, $\mathbb{R}/\mathbb{Z}$ could denote either the quotient space obtained by identifying all integers with each other, on the one hand, or the quotient group of the reals modulo 1, on the other hand.
Is there an alternate notation for the first usage ‐ for collapsing a subset to a point?
I vaguely recall once seing $X//A$ for this. Is that a wholly idiosyncratic and isolated usage?