theorem
ERealFunction.convexOn_univ_toReal_normPowerEnvelope_of_mem_gammaZero
{H : Type u}
[NormedAddCommGroup H]
[InnerProductSpace ℝ H]
[CompleteSpace H]
(f : H → ↑(Set.Ioi ⊥))
(γ : PosReal)
(p : ↑(Set.Ici 1))
(hf : f ∈ Γ₀(H))
(hp : 1 < ↑p)
:
_root_.ConvexOn ℝ Set.univ fun (x : H) => (normPowerEnvelope f p γ x).toReal
Proposition 12.15 (1): if f ∈ Γ₀(H), γ ∈ ℝ_{++}, and p > 1, then the real-valued
representative of the p-power envelope is convex on H.
theorem
ERealFunction.normPowerEnvelope_mem_Ioo_of_mem_gammaZero
{H : Type u}
[NormedAddCommGroup H]
[InnerProductSpace ℝ H]
[CompleteSpace H]
(f : H → ↑(Set.Ioi ⊥))
(γ : PosReal)
(p : ↑(Set.Ici 1))
(hf : f ∈ Γ₀(H))
(hp : 1 < ↑p)
(x : H)
:
normPowerEnvelope f p γ x ∈ Set.Ioo ⊥ ⊤
Proposition 12.15 (2): if f ∈ Γ₀(H), γ ∈ ℝ_{++}, and p > 1, then the p-power
envelope is real-valued at every point of H.
theorem
ERealFunction.continuous_toReal_normPowerEnvelope_of_mem_gammaZero
{H : Type u}
[NormedAddCommGroup H]
[InnerProductSpace ℝ H]
[CompleteSpace H]
(f : H → ↑(Set.Ioi ⊥))
(γ : PosReal)
(p : ↑(Set.Ici 1))
(hf : f ∈ Γ₀(H))
(hp : 1 < ↑p)
:
Continuous fun (x : H) => (normPowerEnvelope f p γ x).toReal
Proposition 12.15 (3): if f ∈ Γ₀(H), γ ∈ ℝ_{++}, and p > 1, then the real-valued
representative of the p-power envelope is continuous on H.
theorem
ERealFunction.exactAt_and_existsUnique_mem_argmin_normPowerEnvelope_of_mem_gammaZero
{H : Type u}
[NormedAddCommGroup H]
[InnerProductSpace ℝ H]
[CompleteSpace H]
(f : H → ↑(Set.Ioi ⊥))
(γ : PosReal)
(p : ↑(Set.Ici 1))
(hf : f ∈ Γ₀(H))
(hp : 1 < ↑p)
(x : H)
:
infimalConvolution.ExactAt f (normPowerKernel p γ) x ∧ ∃! y : H, y ∈ Argmin fun (z : H) => ↑(f z) + ↑(normPowerKernel p γ (x - z))
Proposition 12.15 (4): for f ∈ Γ₀(H), γ ∈ ℝ_{++}, p > 1, and every x ∈ H, the
infimal convolution defining the p-power regularization is exact at x, and the translated
objective y ↦ f y + ‖x - y‖^p / (γ p) has a unique global minimizer.