∀ (G : Type u_1) [inst : Group G] (α : Type u_2) [inst_1 : MulAction G α] (s : Set α),
  instMulActionSubtypeMemSubgroupStabilizerSetElem G α s =
    { toSMul := SMul.ofStabilizer G α s, mul_smul := ⋯, one_smul := ⋯ }