InformationTheory.Shannon.EPI.Case1.SmoothingLimit
Explicit-density de Bruijn producer and explicit density-form EPI #
This file replaces the canonical Measure.rnDeriv representative in the de Bruijn
producer with an explicit density argument.
The canonical rnDeriv representative is Classical.choose-derived and generically
non-differentiable, so IsRegularDensityV2 (full pointwise regularity) cannot be
transported from a smoothed density conv(pX, g_t) to a mere a.e.-equal canonical
representative. The producer here accepts an explicit pX : ℝ → ℝ that the caller
controls.
Main definitions #
isDeBruijnRegularityHyp_of_explicitDensity: explicit-density de Bruijn producer.
Main statements #
entropy_power_inequality_of_density_explicit: explicit-density density-form EPI.
Implementation notes #
All hypotheses (hpX_nn/hpX_meas/hpX_int/hpX_law/hpX_mom/hreg_pX/hnorm_pX/hready_pX)
are regularity preconditions, not load-bearing: they assert pointwise regularity of the
explicit density, normalization, and finite Fisher information, but do not encode the
de Bruijn / Fisher-monotonicity inequality core.
InformationTheory.Shannon.EPICase1SmoothingLimit.isDeBruijnRegularityHyp_of_explicitDensity
sourceExplicit-density variant of isDeBruijnRegularityHyp_of_methodX_unitnoise.
Replaces the canonical rnDeriv prefix with an explicit pX : ℝ → ℝ argument,
allowing the caller to pass a pointwise-regular density such as conv(pX_base, g_t)
directly without having to transport IsRegularDensityV2 through an a.e.-equality.
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Instances For
Used by
InformationTheory.Shannon.EPICase1SmoothingLimit.isHeatFlowEndpointRegular_of_map_eq_rnDeriv
sourceEquations
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Instances For
Used by
InformationTheory.Shannon.EPICase1SmoothingLimit.entropy_power_inequality_of_density_explicit
sourceExplicit-density variant of entropy_power_inequality_of_density.
States regularity hypotheses for pX, pY, pXY as explicit ℝ → ℝ arguments
rather than canonical rnDeriv representatives, and adds withDensity links.
All hypotheses are regularity preconditions; they do not encode the EPI inequality core.
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Used by
InformationTheory.Shannon.EPICase1SmoothingLimit.isBlachmanConvReady_convGaussian_gaussian
sourceBlachman bridge — IsBlachmanConvReady (convDensityAdd p_base g_τ) (gaussianPDFReal 0 v).
The explicit entropy_power_inequality_of_density_explicit requires, for each density
witness q, a hready : ∀ v ≠ 0, IsBlachmanConvReady q (gaussianPDFReal 0 v). When q is
itself a conv-density convDensityAdd p_base g_τ, the bare IsBlachmanConvReady (conv …) (g_v)
shape is supplied by the asymmetric producer isBlachmanConvReady_convDensityAdd_gaussian_asym:
take its second arm pY := gaussianPDFReal 0 ⟨v/2,_⟩ at time v/2, so its second factor
convDensityAdd g_{v/2} g_{v/2} collapses to gaussianPDFReal 0 v via the variance-doubling
identity convDensityAdd_gaussian_variance_double.
All hypotheses are regularity preconditions; the conclusion (19-field bundle) is genuinely derived. No bundled analytic core.
Used by
InformationTheory.Shannon.EPICase1SmoothingLimit.memLp_two_of_map_eq_gaussianReal_one
sourceUsed by
InformationTheory.Shannon.EPICase1SmoothingLimit.map_eq_withDensity_ofReal_rnDeriv
sourceUsed by
InformationTheory.Shannon.EPICase1SmoothingLimit.integrable_sq_mul_of_map_eq_withDensity_ofReal
sourceUsed by
InformationTheory.Shannon.EPICase1SmoothingLimit.map_smoothed_eq_withDensity_convDensityAdd
sourceUsed by
InformationTheory.Shannon.EPICase1SmoothingLimit.canonical_base_density_regularity
sourceUsed by
InformationTheory.Shannon.EPICase1SmoothingLimit.smoothing_density_regularity
sourceUsed by
InformationTheory.Shannon.EPICase1SmoothingLimit.entropyPower_smoothed_epi_perT
sourcePer-t smoothing EPI.
For smoothed variables X_t = X + √t·Z_X, Y_t = Y + √t·Z_Y (independent standard-normal
noises), the entropy-power inequality holds at every fixed t > 0. Proved by instantiating the
explicit-density EPI entropy_power_inequality_of_density_explicit at X := X_t,
Y := Y_t, with conv-density witnesses convDensityAdd p_base g_τ (canonical-base densities
convolved with the smoothing Gaussian), and discharging all regularity obligations via the
public conv-Gaussian producers (regularity / normalization / Blachman / finite Fisher /
finite entropy).
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Used by
InformationTheory.Shannon.EPICase1SmoothingLimit.iIndepFun_liftMeasure4_of_indep
sourceUsed by
InformationTheory.Shannon.EPICase1SmoothingLimit.entropy_power_add_ge_of_finite_variance
sourceFinite-variance classical EPI (Real, no noise).
The base-level entropy-power inequality N(X+Y) ≥ N(X) + N(Y) for absolutely
continuous, finite-variance, independent X, Y — with NO smoothing noise. Obtained
by lifting to a 3-noise space, instantiating the per-t smoothing EPI
entropyPower_smoothed_epi_perT at every t > 0, and pushing t → 0⁺ via heat-flow
endpoint continuity (heatFlowEntropyPower_continuousWithinAt_zero) with
le_of_tendsto_of_tendsto.
The entropy-integrability hypotheses hX_ent/hY_ent/hent_sum are regularity
preconditions (finite differential entropy of the marginals/sum); they do NOT encode
the EPI conclusion (load-bearing-free).
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InformationTheory.Shannon.EPICase1SmoothingLimit.entropyPowerExt_add_ge_of_finite_variance
sourceFinite-variance classical EPI (ext, ℝ≥0∞).
The entropyPowerExt (ℝ≥0∞-valued) version of entropy_power_add_ge_of_finite_variance.
Under the same hypotheses, Nₑ(X+Y) ≥ Nₑ(X) + Nₑ(Y) in ℝ≥0∞. Obtained by lifting the
Real inequality through entropyPowerExt_of_ac_integrable
(entropyPowerExt μ = ENNReal.ofReal (entropyPower μ) for a.c. + finite-entropy μ) and
ENNReal.ofReal_add (both entropy powers nonneg).
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Infinite-variance a.c. classical EPI #
The infinite-variance case entropyPowerExt_add_ge_infinite_variance is established
in EPI/InfiniteVariance/Capstone.lean (compact-support truncation + finite-variance
EPI + Gibbs + DCT). It cannot reside here because this file is upstream of the
truncation module (import cycle).