ThmDex – An index of mathematical definitions, results, and conjectures.
Proof P453 on R738: Left and right cosets coincide in Abelian group
P453
Applying commutativity yields \begin{equation} g H : = \{ g h \in h \in H \} = \{ h g \mid h \in H \} = : H g \end{equation} $\square$