On inclusion relations of weighted L^p-type spaces defined in terms of weight function matrices
Pith reviewed 2026-05-18 09:54 UTC · model grok-4.3
The pith
Inclusion relations of weighted L^p spaces are determined by relations between their weight function matrices.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Weighted L^p-type spaces are introduced via weight function matrices, and the inclusion between two such spaces holds exactly when the matrices satisfy a certain comparison condition. This condition is made explicit and applied to matrices coming from a single weight function together with a real parameter. In the ultradifferentiable context the same characterization shows that Beurling-Björck weights need not obey the convexity condition that is standard in the Braun-Meise-Taylor theory, as demonstrated by an explicit counterexample.
What carries the argument
The weight function matrix, a collection of individual weight functions arranged in matrix form, which enters the definition of the space norm and thereby controls the size of functions in the space.
If this is right
- Inclusions between the spaces reduce to verifiable conditions on the entries of the matrices.
- For the special case of matrices built from one weight function and a parameter, the inclusions simplify to relations involving that weight and the parameter value.
- The spaces coincide with standard L^p spaces precisely when the matrix entries satisfy appropriate boundedness or decay conditions.
- Translation invariance of the spaces depends on the growth properties of the weight functions in the matrix.
- The same matrix comparison applies when the weighting is transferred to the Fourier transform side.
Where Pith is reading between the lines
- The matrix-based description could be used to compare weighted versions in other classes of function spaces.
- The explicit counterexample separating the two ultradifferentiable weight settings can be used to check which properties require convexity.
- The treatment of Fourier-side weighting indicates the framework extends naturally to harmonic analysis.
Load-bearing premise
The weight function matrices satisfy positivity, measurability, and growth conditions that ensure the weighted expressions define valid Banach space norms.
What would settle it
A pair of weight function matrices where the L^p spaces include each other even though the matrix comparison condition fails.
read the original abstract
We introduce new weighted $L^p$-type spaces defined in terms of weight function matrices and characterize the inclusion relations in terms of the defining matrices. Moreover, we provide a detailed study concerning the coincidence with the common (non-weighted) $L^p$-spaces, the (non-)triviality of such weighted spaces and investigate their translation invariance. The obtained results are then applied to particular weight function matrices which are expressed in terms of one single weight function and a positive real parameter. Also variations of this new weighted setting are discussed; more precisely weighted Banach (sub-)spaces of $L^p$ and when weighting the Fourier image of appropriate Banach spaces of functions. The general framework allows to describe the known ultradifferentiable weight function setting by Beurling-Bj\"{o}rck which is more original than the approach presented by Braun, Meise and Taylor. When applying the characterization of the inclusion relations to Beurling-Bj\"{o}rck-type spaces we are able to emphasize the difference between both ultradifferentiable weight function settings: We construct a technical (counter-)example which is a weight in the sense of Beurling Bj\"{o}rck but violates the standard and crucial convexity condition needed in the Braun-Meise-Taylor setting.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript introduces weighted L^p-type spaces via matrices of weight functions satisfying positivity, measurability and growth conditions. It characterizes inclusion relations between these spaces by direct comparison of the defining matrix entries, studies their coincidence with ordinary L^p spaces, (non-)triviality and translation invariance, and applies the results to matrices generated from a single weight function together with a positive parameter. Variations such as weighted Banach subspaces of L^p and weighted Fourier images are discussed. The framework is then used to embed the Beurling-Björck ultradifferentiable setting and to distinguish it from the Braun-Meise-Taylor setting by exhibiting an explicit weight that satisfies the former axioms but violates the convexity condition required by the latter.
Significance. If the matrix-based characterization and the counter-example construction are correct, the work supplies a uniform language for comparing weighted L^p spaces and clarifies a concrete distinction between two standard ultradifferentiable weight-function frameworks. The explicit counter-example is a concrete, falsifiable contribution that can be checked independently.
major comments (1)
- [§4] §4 (counter-example construction): the verification that the constructed weight satisfies all Beurling-Björck axioms (subadditivity, continuity, etc.) while failing the Braun-Meise-Taylor convexity condition is only sketched; an explicit computation of the associated matrix entries and a direct check of the convexity inequality at a concrete point would strengthen the claim that the two settings are genuinely distinct.
minor comments (2)
- [§2] Notation for the matrix-valued weight functions is introduced in §2 but the precise measurability and growth hypotheses are restated in several later sections; a single consolidated list of standing assumptions would improve readability.
- [Theorem 3.2] The statement of Theorem 3.2 on inclusion relations refers to “the natural ordering of matrices” without recalling the precise partial order used; a brief reminder or cross-reference to Definition 2.4 would help.
Simulated Author's Rebuttal
We thank the referee for the careful reading of the manuscript and the constructive suggestion regarding the counter-example. We address the comment below and will revise the manuscript to incorporate the requested details.
read point-by-point responses
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Referee: [§4] §4 (counter-example construction): the verification that the constructed weight satisfies all Beurling-Björck axioms (subadditivity, continuity, etc.) while failing the Braun-Meise-Taylor convexity condition is only sketched; an explicit computation of the associated matrix entries and a direct check of the convexity inequality at a concrete point would strengthen the claim that the two settings are genuinely distinct.
Authors: We agree that the verification of the counter-example in §4 is presented in a condensed form. In the revised manuscript we will expand this part by supplying explicit formulas for the matrix entries generated by the chosen weight function. We will also perform a direct numerical check of the convexity inequality at a concrete point (e.g., evaluating the relevant expressions at a specific positive real number) to demonstrate explicitly that the Braun-Meise-Taylor condition fails while all Beurling-Björck axioms continue to hold. These additions will make the distinction between the two ultradifferentiable frameworks fully verifiable without changing any of the stated theorems. revision: yes
Circularity Check
No significant circularity detected
full rationale
The paper introduces weighted L^p-type spaces via weight function matrices satisfying standard positivity, measurability and growth conditions, then characterizes inclusion relations by direct comparison of those matrix entries. It further constructs an explicit technical counterexample weight that satisfies the Beurling-Björck axioms while violating the convexity condition required in the Braun-Meise-Taylor framework. These steps rest on external prior definitions of the two ultradifferentiable settings and ordinary functional-analysis axioms; no load-bearing claim reduces by construction to a fitted parameter, self-definition, or self-citation chain internal to the paper. The derivation therefore remains self-contained against the stated hypotheses.
Axiom & Free-Parameter Ledger
axioms (1)
- domain assumption Weight function matrices satisfy positivity, measurability, and suitable growth conditions so that the associated spaces are well-defined Banach spaces.
Reference graph
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