InformationTheory

InformationTheory.Shannon.FisherInfo.DeBruijnAssembly

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Per-time de Bruijn identity — assembly #

Aggregates the submodules that prove the per-time de Bruijn identity debruijnIdentityV2_holds_assembled for a general X. This file is placed downstream of the atom supplier FisherInfo/DeBruijnPerTime.lean (which imports FisherInfo/DeBruijn.lean) so that the assembly can use those atoms without an import cycle.

Implementation notes #

The per-time identity is assembled from the atoms by: identifying the path density with convDensityAdd; rewriting the entropy as ∫ negMulLog pPath; differentiating under the integral (entropy_hasDerivAt_via_parametric); applying the heat equation (heatFlow_density_heat_equation); integrating by parts (debruijn_ibp_step); and matching the result to (1/2) · fisherInfoOfDensityReal h_reg.density_t (fisher_from_logDeriv). The regularity discharges (Gaussian-tail domination, integrand measurability, global -ness, chain-rule plumbing) are factored into named private lemmas in the submodules.