Stabilizer of Subset Product Action on Power Set

Theorem
Let $\struct {G, \circ}$ be a group whose identity is $e$.

Let $\powerset G$ be the power set of $\struct {G, \circ}$.

Let $S \in \powerset G$.

Let $*$ be the group action on $S$ defined as:
 * $\forall g \in G: g * S = g \circ S$

where $g \circ S$ is the subset product $\set g \circ S$.

Then the stabilizer of $S$ in $\powerset G$ is the set:
 * $\Stab S = \set {g \in G: g \circ S = S}$

Proof
From the definition of stabilizer:


 * $\Stab S = \set {g \in G: g * S = S}$

The result follows from the definition of the group action $*$ given.

Also see

 * Group Action on Subset of Group
 * Stabilizer of Coset Action on Set of Subgroups
 * Orbit of Subgroup under Coset Action is Coset Space