Defining a map based on a group action on left cosets

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If $H$ is subgroup of $G$ such that the index of $H$ in $G$ is $n$ and $\pi_H$ is the permutation representation of the action of $G$ on the left cosets of $H$, is $\pi_H$ a map from $H$ to $S_n$? I am a bit confused about how $\pi_H$ relates to the symmetric group.

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The map $\pi_H$ is technically a homomorphism from $G$ to $S_X$ where $X = G/H$. Now if $G$ has finite index, then $|X| = n$, and so $S_X \cong S_n$. Under this isomorphism you can think of $\pi_H$ as a homomorphism from $G$ to $S_n$.