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2501.01750

Decomposition of discontinuous flows of diffeomorphisms: jumpings, geometrical and topological aspects

Lourival Lima, Paulo Ruffino

correctmedium confidence
Category
Not specified
Journal tier
Specialist/Solid
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper’s Theorem 3.5 correctly proves that a Marcus SDEJ flow φt admits a local decomposition φt = Ft ∘ Gt up to a stopping time and derives the explicit Marcus equations governing Ft and Gt using a generalized Itô–Ventzel–Kunita/Leibniz formula for flows with infinitely many jumps. In contrast, the candidate solution misidentifies the SDE for the vertical factor Gt as being driven by the naive vertical projection XV of X and makes Ft depend on Gt, contradicting the paper’s nontrivial ‘tilted’ vertical component and the autonomous right-invariant equation for Ft. See the paper’s decomposition statement and equations (Theorem 3.5 and its proof) and the Leibniz formula used there .

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The manuscript advances decomposition theory for flows with jumps by allowing arbitrary semimartingale drivers and by providing explicit component dynamics, grounded in a carefully established Leibniz rule for Marcus flows. The results are correct and of interest to specialists in stochastic flows and geometric SDEs. Minor clarifications (tilted vertical subspaces, stopping-time criterion, and a schematic of the proof) would enhance accessibility.