The left coset space 
of a group 
by a subgroup 
is the set of left cosets 
. It is a quotient space
when 
is a topological
group and 
is closed. It is a quotient group precisely when
is a normal
subgroup.
Coset Space
See also
Coset, Normal Subgroup, Quotient Group, Quotient SpaceExplore with Wolfram|Alpha
References
Rotman, J. J. An Introduction to the Theory of Groups, 4th ed. New York: Springer-Verlag, 1995.Cite this as:
Weisstein, Eric W. "Coset Space." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/CosetSpace.html