Coset Space: Notation
If we are (as is usual) concerned at a particular time with only the right or the left coset space, then the superscript is usually dropped.
Thus the notation $G / H$ is used for both the right and left coset space.
If, in addition, $H$ is a normal subgroup of $G$, then $G / H^l = G / H^r$ and the notation $G / H$ is then unambiguous anyway.
This notation is rarely encountered, and can be a source of confusion.