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2110.04501

LEFT REGULAR REPRESENTATIONS OF GARSIDE CATEGORIES I. C*-ALGEBRAS AND GROUPOIDS

Xin Li

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

Audit review

The paper’s Theorem 6.25 proves an inclusion-preserving bijection between closed I_C⋉Ω-invariant subspaces and admissible, C-invariant, max∞_S-closed pairs (T,D); it proceeds via (i) representing points of Ω by S-normal words with uniqueness, (ii) the maps X ↦ (T(X),D(X)) and (T,D) ↦ –(T,D), and (iii) a compactness/normal-form argument to show these maps are inverses. The candidate solution follows the same structure and uses the same key ingredients (normal forms, greedy head/normalization, compactness, and the max∞-closure criterion). Its only discrepancies are minor notational choices (writing S; for the left inverse hull and calling Ω “tight/cover-respecting” at once). Core logical steps and hypotheses align with the paper’s statements and lemmas, including Lemma 6.17 (normal-word representation and uniqueness), Lemma 6.22 (equivalence of admissibility/invariance/closure under the maps), Proposition 6.14 (greedy head), and Theorem 6.25 itself. Therefore, both are correct and substantially the same proof. See Theorem 6.25 for the classification, which is exactly as the model states ; uniqueness and representation by normal words ; the definition of (T(X),D(X)) and the characterization of admissibility/invariance/max∞-closedness via X ; and the greedy head/normalization facts used to propagate invariance .

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The manuscript provides a clean and general classification of closed invariant subspaces for groupoids from Garside categories. The use of normal forms to parametrize Ω and the careful max∞-closure analysis are both technically solid and conceptually clarifying. A few minor notational clarifications and brief reminders of topological basics in Ω would enhance readability, but the results stand on firm ground.