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2207.14737

Relatively Anosov Representations via Flows I: Theory

Feng Zhu, Andrew Zimmer

correctmedium confidence
Category
Not specified
Journal tier
Strong Field
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper proves the equivalence between (A) boundary–map relative Anosov, (B) existence of a contracting flow for some weak cusp space, and (C) a contracting flow for every Groves–Manning cusp space (Theorem 1.3) using a direct flow–bundle construction on G(X) and a careful thick–thin analysis of Groves–Manning cusps, together with singular value growth for peripheral subgroups and a dominated-splitting equivalence on Hom-bundles (Definition 1.2, Proposition 4.9, Theorem 9.1, Proposition 13.7) . The candidate solution outlines a different, standard approach: (A)⇒(C) via KLP’s relativized uniform gap along relative geodesics plus BCLS/BPS graph-transform arguments; (B)⇒(A) by deducing the strong dynamics preserving property from exponential contraction; and (C)⇒(B) trivially. This is consistent with known theory, albeit at a sketch level, and slightly overreaches by asserting independence across all weak cusp models via Mineyev’s flow space (not needed for the theorem and not shown in the paper). Net: both are correct; the paper’s proof is complete and self-contained for the stated equivalence; the model gives a plausible alternative sketch.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The manuscript gives a coherent, comprehensive flow-based characterization of relatively Anosov representations and proves the expected equivalence with the boundary-map definition, including the difficult direction producing contracting norms on any Groves–Manning cusp space. The arguments appear correct and the quantitative consequences are valuable. Minor expository tweaks would further improve readability and situate the results relative to alternate frameworks (KLP, BCLS/BPS).