Definition:Coset/Right Coset

Definition
Let $G$ be a group, and let $H \le G$. The right coset of $y$ modulo $H$, or right coset of $H$ by $y$, is:


 * $H y = \left\{{x \in G: \exists h \in H: x = h y}\right\}$

This is the equivalence class defined by right congruence modulo $H$.

Alternatively, it can be viewed as an extension of the idea of the subset product:


 * $H y = H \left\{{y}\right\}$