
In Peter Szekeres's text "A Course in Modern Mathematical Physics", problem 2.19 part (a) is as follows:
If $H$ is any subgroup of a group $G$ define the action of $G$ on the set of left cosets $G/H$ by $g : g'H \mapsto g g' H$.
(a) Show that this is always a transitive action of $H$ on $G$.
Th...