arXiv:2608.00370v1
Abstract
For stochastic differential equations, we establish a relationship between the measure-theoretic entropy of the stochastic flow and the rate of volume growth of stable submanifolds under iteration. By combining the result of Kifer and Yomdin (1988), we show that under a suitable integrability condition, for systems with coefficients, the measure-theoretic entropy is upper semicontinuous with respect to the coefficients of SDEs.
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Not a correctness certificate. A “Correct” result may include yellow typos or minor formal corrections that do not affect substantive soundness. It means this audit found no unresolved substantive error under the stated criteria; it does not replace expert scrutiny or formal verification.
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Detailed mathematical audit
01Statements2 reported findingsContains wrong statements
The main upper-semicontinuity theorem is false under the stated convergence hypothesis. A rescaled compactly supported deterministic flow gives coefficients converging uniformly to zero while preserving positive metric entropy and concentrating its invariant measure at a zero-entropy fixed point. The two application theorems impose additional recurrence and nondegeneracy hypotheses, so this counterexample does not disprove them, but their printed proofs depend on the invalid general theorem and do not independently establish their conclusions.
Uniform convergence of coefficients does not imply upper semicontinuity of entropy
Pages 14–15 · Theorem 3.7 · arXiv:2608.00370v1
Choose a smooth compactly supported vector field on some whose flow has a compact invariant probability measure with positive time-one entropy; for example, embed a smooth suspension of a horseshoe in Euclidean space and extend its vector field through a tubular neighborhood with compact support. For , set and , while . The flow satisfies . Hence , every coefficient is with all derivatives bounded for each fixed , and every integral in (3.26) is finite. If is the pushforward of by , then and , whereas the limiting zero flow has . All printed hypotheses hold, but the asserted inequality fails. A valid theorem needs substantially stronger, uniform smooth control than convergence alone.
Full paper, version 1 ↗The application statements are not independently established
Pages 16–18 · Theorems 4.2 and 4.4 · arXiv:2608.00370v1
These theorems add a uniform Lyapunov condition and nondegeneracy of the diffusion on the relevant set, so the deterministic rescaling counterexample to Theorem 3.7 does not directly apply. Their proofs, however, consist of invoking Theorem 3.7 after Proposition 4.1 or Lemma 4.3. Since Theorem 3.7 is false and no replacement argument exploiting the additional hypotheses is supplied, a nontrivial proof obligation remains: one must derive entropy control uniform in , rather than merely finiteness of every fixed system's smooth norms. No proof or counterexample for these narrower statements is supplied here.
02Proofs5 reported findingsContains incorrect or incomplete proofs
The proof of the main theorem cannot be repaired under its printed hypotheses because the theorem has an explicit counterexample. Two earlier arguments also contain independent substantive gaps: Lemma 3.3 uses a false entropy identity for a fixed partition, and Theorem 3.5 treats merely measurable Oseledets data as continuous on an arbitrary compact set and omits the zero-positive-exponent case. Two mechanical notation errors are reported separately in yellow.
The argument lacks the uniform smooth control excluded by the counterexample
Page 15 · Equations (3.27)–(3.29) · arXiv:2608.00370v1
Equation (3.29) makes the local-volume term vanish separately for each by allowing the differentiability order to tend to infinity, but the hypotheses contain no bound uniform in on the higher derivatives or on the associated local complexity. The rescaled-flow construction in the statements finding satisfies (3.26) for every fixed while retaining positive entropy, so the asserted conclusion cannot follow. Repair classification: No repair under the stated hypotheses; the theorem must be strengthened by a uniform topology or explicit uniform tail-entropy estimate.
The proof uses a false fixed-partition entropy identity
Pages 6–8 · display following Equation (3.6) · arXiv:2608.00370v1
The proof writes for the same fixed partition . In general only the system entropy scales as ; for a fixed partition the correct -block relation uses . Substituting that block changes the conditional-partition argument and must be propagated through (3.1)–(3.6). Repair classification: Plausible repair only, by giving the standard local-entropy proof with the full -block partition; the manuscript does not do so.
The Lyapunov-chart construction omits measurable-selection and exponent cases
Pages 11–14 · proof of Theorem 3.5, especially Equations (3.20)–(3.21) · arXiv:2608.00370v1
The proof first infers from that a positive Lyapunov exponent exists, which does not follow from Ruelle's inequality. It then asserts that the Oseledets bundles and the measurable chart-size and angle functions are continuous on the arbitrary compact set for almost every noise realization. Oseledets theory supplies measurability, while a Lusin argument gives continuity only after restricting to a suitably chosen large-measure compact subset and controlling varying multiplicities. Consequently the positive infima defining and the subsequent finite covering are not established in the claimed scope. Repair classification: No repair supplied; the missing exponent case and a correct Pesin-block selection must be incorporated throughout the volume comparison.
The separated-pair formula repeats the base point
Page 6 · paragraph before Lemma 3.3 · arXiv:2608.00370v1
For distinct , the printed separation condition compares with . Replace in that comparison by . The surrounding phrase 'for any ' and every later use as an -separated set determine this correction uniquely.
The positive logarithm is printed as a positive part of its argument
Page 11 · definition immediately following · arXiv:2608.00370v1
The paper prints . Replace this by . The notation, the logarithmic growth-rate formulas, and the integrability conditions determine the intended correction mechanically; leaving the printed definition literal would invalidate the stated growth normalization.
03Novelty0 reported findingsNo non-novelty findings
No non-novelty findings.