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2105.05491

CONTINUITY OF MEASURE-DIMENSION MAPPINGS

Liangang Ma

correctmedium confidence
Category
math.DS
Journal tier
Specialist/Solid
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper’s Theorem 2.8 (lower semicontinuity of dimU under setwise convergence, assuming countable stability) and Theorem 2.9 (upper semicontinuity of dimL under setwise convergence, no extra assumption) match exactly the task and are proven by the same subsequence/indicator-function arguments used by the candidate. The paper’s proofs hinge on: (i) countable stability to pass dimensions through a countable union in Theorem 2.8, and (ii) setwise convergence implying convergence of νn(A) for fixed measurable A via indicator functions in both theorems; the candidate’s solution mirrors these steps, choosing full-measure (resp. positive-measure) sets and applying setwise convergence to indicators to transfer nullity/positivity to the limit. Hence, both arguments are correct and essentially identical in structure to the official proofs in the paper. See the statements of Theorems 2.8 and 2.9 and their proofs in the paper for details ; the definitions of dimL, dimU and the setwise topology appear earlier in the paper .

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The manuscript establishes precise semicontinuity properties of induced measure-dimension mappings under setwise convergence with succinct, correct proofs and contextual counterexamples. While the contributions are modest, they clarify where setwise topology suffices and what additional structure (countable stability) is needed. A few minor expository tweaks would further improve accessibility.