∀ {Ω : Type u_1} {E : Type u_2} {mΩ : MeasurableSpace Ω} {P : MeasureTheory.Measure Ω} [inst : NormedAddCommGroup E]
  [inst_1 : MeasurableSpace E] [BorelSpace E] {X : Ω → E} [inst_3 : NormedSpace ℝ E] (L : StrongDual ℝ E),
  ProbabilityTheory.HasGaussianLaw X P →
    MeasureTheory.charFunDual (MeasureTheory.Measure.map X P) L =
      Complex.exp (↑(∫ (x : Ω), (⇑L ∘ X) x ∂P) * Complex.I - ↑(ProbabilityTheory.variance (⇑L ∘ X) P) / 2)