Cohomology classes of complex approximable algebras
Pith reviewed 2026-05-24 13:07 UTC · model grok-4.3
The pith
Over the complex numbers, the infinite Weil divisor associated to an approximable graded algebra has finite cohomology class.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The paper proves that over the complex numbers the infinite Weil divisor associated to any approximable graded algebra has finite cohomology class.
What carries the argument
The correspondence, established in prior work, that associates each approximable graded algebra to an infinite Weil divisor and thereby reduces the question to the finiteness of its cohomology class.
Load-bearing premise
The prior association between approximable graded algebras and infinite Weil divisors continues to hold when the base field is restricted to the complex numbers.
What would settle it
An explicit example of an approximable graded algebra defined over the complex numbers whose associated infinite Weil divisor has infinite-dimensional cohomology.
read the original abstract
Huayi Chen introduces the notion of an approximable graded algebra, which he uses to prove a Fujita-type theorem in the arithmetic setting, and asked if any such algebra is the graded ring of a big line bundle on a projective variety. This was proved to be false in a previous paper of the author's, who subsequently proved that any such algebra is associated to an infinite Weil divisor. In this paper, we show that over the complex numbers, this infinite Weil divisor necessarily has finite cohomology class.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper shows that over the complex numbers, the infinite Weil divisor associated to an approximable graded algebra necessarily has finite cohomology class. This builds on the author's prior result that any approximable graded algebra is associated to an infinite Weil divisor (following Chen's introduction of the notion for an arithmetic Fujita-type theorem).
Significance. If the result holds, it establishes a finiteness property for the cohomology class in the complex case, providing a concrete restriction that may help relate the arithmetic constructions to complex geometry. The manuscript relies on the prior independent association without introducing new free parameters or ad-hoc axioms.
Simulated Author's Rebuttal
We thank the referee for their report. The summary correctly describes the paper's contribution: over the complex numbers, the infinite Weil divisor associated to an approximable graded algebra has finite cohomology class, building on the prior association result. The recommendation is listed as uncertain, but the major comments section contains no specific points or concerns. We therefore provide no point-by-point responses below.
Circularity Check
Minor self-citation to prior association; central claim independent
full rationale
The paper's derivation relies on the author's prior result associating approximable graded algebras to infinite Weil divisors, but the new claim (finite cohomology class over C) adds independent content via restriction to the complex numbers and does not reduce any quantity to a fitted input, self-definition, or self-citation chain within this manuscript. No equations or steps in the provided abstract or description exhibit the enumerated circular patterns; the prior work supplies external support rather than forcing the result by construction.
Axiom & Free-Parameter Ledger
axioms (2)
- domain assumption Definition of approximable graded algebra (Chen)
- domain assumption Association of such algebras to infinite Weil divisors (prior paper)
discussion (0)
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