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2201.13426

Maximal Equivariant Compactifications

Michael Megrelishvili

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

Audit review

The paper’s main theorem (Theorem 4.8) establishes A βG B iff for all neighborhoods V of the identity, VA β VB, and in normal spaces this is equivalent to V cl(A) ∩ V cl(B) ≠ ∅; the proof proceeds via the general proximity/uniformity framework (Theorem 4.1 and the maximal compatible uniformity) and is coherent and correct . The candidate solution proves the same equivalence by an averaging argument using Haar measure to produce RUCG separators and a uniform-continuity contradiction in the converse direction. It is essentially correct once one makes a minor, standard correction to the change-of-variables step (use left translations and F(x)=∫φ(g)f(g^{-1}·x)dμ(g)); it also properly uses local compactness of G and the normal-space reduction. Notably, the paper’s abstract states an existential quantifier (∃V) while the body and proof correctly use a universal quantifier (∀V); this appears to be a minor typographical slip in the abstract that should be fixed .

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The paper gives a sharp and conceptually clean characterization of the maximal G-proximity for locally compact group actions using proximities and equiuniformities, culminating in Theorem 4.8. The proofs are correct and well structured; the dependence on local compactness is properly treated. The only issue I noticed is a quantifier mismatch between the abstract (∃V) and the main theorem (∀V), which should be corrected. A brief comment on the normal-space corollary would further aid readability.