Polarizations of Artin monomial ideals
Pith reviewed 2026-05-24 10:15 UTC · model grok-4.3
The pith
Any polarization of an Artin monomial ideal defines a triangulated ball on the join of simplex boundaries.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
We show that any polarization of an Artin monomial ideal defines a triangulated ball. Geometrically, polarizations of ideals containing (x1^a1, …, xn^an) define full-dimensional triangulated balls on the sphere which is the join of boundaries of simplices of dimensions a1-1, ⋯, an-1. We prove that every full-dimensional Cohen-Macaulay sub-complex of this joined sphere is of this kind, and these balls are constructible. Such a triangulated ball has a dual cell complex which is a sub-complex of the product of simplices of dimensions a1-1, ⋯, an-1. We prove that this cell complex gives cellular minimal free resolution of the Alexander dual ideal of the triangulated ball.
What carries the argument
Polarization of an Artin monomial ideal, realized geometrically as a full-dimensional triangulation of the join of simplex boundaries.
If this is right
- The triangulated balls obtained this way are constructible.
- The dual cell complex inside the product of simplices supplies a cellular minimal free resolution of the Alexander dual ideal.
- When the product of simplices is a hypercube, the dual cell complexes classify all polarizations in a stated range of examples.
- Kalai's squeezed balls arise directly as polarizations of Artin monomial ideals.
Where Pith is reading between the lines
- The geometric correspondence supplies an explicit way to build cellular resolutions for Alexander duals of these monomial ideals.
- The classification technique used in the hypercube case may extend to other products of simplices beyond the hypercube.
- The recovery of squeezed balls suggests that other known families of triangulations could be recovered algebraically via polarizations.
Load-bearing premise
The algebraic definition of a polarization matches the geometric triangulation of the joined sphere without further restrictions.
What would settle it
An explicit polarization of some Artin monomial ideal whose associated complex is not a triangulated ball, or a full-dimensional Cohen-Macaulay subcomplex of the joined sphere that cannot be obtained from any polarization.
Figures
read the original abstract
We show that any polarization of an Artin monomial ideal defines a triangulated ball. This proves a conjecture of A.Almousa, H.Lohne and the first author. Geometrically, polarizations of ideals containing $(x_1^{a_1}, \ldots, x_n^{a_n})$ define full-dimensional triangulated balls on the sphere which is the join of boundaries of simplices of dimensions $a_1-1, \cdots, a_n-1$. We prove that every full-dimensional Cohen-Macaulay sub-complex of this joined sphere is of this kind, and these balls are constructible. Such a triangulated ball has a dual cell complex which is a sub-complex of the product of simplices of dimensions $a_1-1, \cdots a_n-1$. We prove that this cell complex gives cellular minimal free resolution of this of the Alexander dual ideal of the triangulated ball. When the product of simplices is a hypercube, using these dual cell complexes we classify in a range examples all polarizations of the Artin monomial ideal. We also show that the squeezed balls of G.Kalai \cite{Ka} derive from polarizations of Artin monomial ideals.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper proves that every polarization of an Artin monomial ideal yields a triangulated ball on the join of boundaries of simplices of dimensions a1-1 to an-1, thereby establishing a conjecture of Almousa, Lohne, and the first author. It shows the converse (every full-dimensional Cohen-Macaulay subcomplex arises this way), proves the balls are constructible, constructs the dual cell complex inside the product of simplices, proves this complex supports the cellular minimal free resolution of the Alexander dual, classifies polarizations in a range of hypercube cases, and derives Kalai's squeezed balls from such polarizations.
Significance. If the central correspondence and resolution claims hold, the work supplies an explicit geometric model and cellular resolution construction for a broad class of monomial ideals, resolves an open conjecture, and connects algebraic polarizations to constructible balls and squeezed spheres. The explicit dual-cell-complex construction and the hypercube classification are concrete strengths that could be used for further computations or generalizations.
minor comments (3)
- [Abstract] Abstract: the sentence on the dual cell complex and Alexander dual resolution is compressed; a parenthetical reference to the relevant theorem number would improve readability.
- [Introduction] The classification statement for the hypercube case is qualified by 'in a range examples'; the precise range (e.g., specific values of a_i or dimension) should be stated explicitly in the introduction or the relevant theorem.
- [Introduction] The reference to Kalai's squeezed balls appears only in the abstract and the final sentence; a short comparison paragraph in the introduction would clarify how the polarization construction recovers or extends the earlier examples.
Simulated Author's Rebuttal
We thank the referee for the positive summary of our results and the recommendation for minor revision. The report accurately captures the main contributions, including the proof of the conjecture, the converse statement, constructibility, the dual cell complex construction supporting the cellular resolution of the Alexander dual, the classification in hypercube cases, and the derivation of Kalai's squeezed balls. Since no specific major comments are provided in the report, we have no individual points to rebut or revise at this stage. We will incorporate any minor editorial suggestions in the revised manuscript.
Circularity Check
No significant circularity identified
full rationale
The paper's central result is a direct proof that polarizations of Artin monomial ideals yield triangulated balls, thereby establishing the cited conjecture of Almousa-Lohne-Fløystad. The abstract and structure indicate that the geometric correspondence, constructibility, dual cell complexes, and cellular resolutions are derived via explicit algebraic and combinatorial arguments within the manuscript itself. The self-citation merely identifies the target conjecture rather than supplying a load-bearing premise or uniqueness theorem; no definitions reduce to their own outputs, no fitted parameters are relabeled as predictions, and no ansatz is imported via prior self-work. The derivation chain is therefore self-contained against external benchmarks.
Axiom & Free-Parameter Ledger
axioms (2)
- domain assumption Standard properties of monomial ideals and their polarizations as defined in the literature on Artin ideals.
- standard math Properties of joins of simplex boundaries and Cohen-Macaulay subcomplexes.
Lean theorems connected to this paper
-
IndisputableMonolith/Foundation/AlexanderDuality.leanalexander_duality_circle_linking unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
We show that any polarization of an Artin monomial ideal defines a triangulated ball... full-dimensional Cohen-Macaulay sub-complex of this joined sphere... dual cell complex... cellular minimal free resolution
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
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