🏗️ $\Theta \rho ϵ\eta \Pi \alpha \tau \pi$🚧 (under construction)

Suppose that $G$ is a group and that $\varnothing \subset H\subseteq G$, then we define $${\displaystyle aH:=\{ah:h\in H\}}$$

Suppose that $G$ is a group and that $\varnothing \subset H\subseteq G$, then we define $${\displaystyle Ha:=\{ha:h\in H\}}$$