One-sided median porous sets and one-sided Muckenhoupt distance functions
Pith reviewed 2026-07-02 02:27 UTC · model grok-4.3
The pith
One-sided median porosity of E is necessary and sufficient for d_E^{-α} to be a one-sided Muckenhoupt A_p weight for some α>0 and 1<p<∞.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
We introduce the notion of one-sided median porosity for subsets E of R. We prove that this condition is necessary and sufficient for the distance weight d_E^{-α} to belong to a one-sided Muckenhoupt A_p class for some α>0 and 1<p<∞. As part of the proof, we obtain new characterizations of one-sided A_p weights and one-sided BMO functions, in terms of medians. We find the precise range of exponents α>0 such that d_E^{-α} belongs to a one-sided A_p class, both for p=1 and for 1<p<∞. In addition, we show that E is median porous if and only if it is both left and right median porous, and we give an example of a one-sided median porous set which is neither median porous nor one-sided weakly poro
What carries the argument
one-sided median porosity, a median-based condition on subsets E of the real line that controls the distribution of E and its complement in intervals
Load-bearing premise
The definitions of one-sided median porosity and the one-sided Muckenhoupt classes are consistent with the median-based characterizations of A_p weights and BMO functions introduced in the paper.
What would settle it
A set E that is one-sided median porous but for which d_E^{-α} fails to satisfy the one-sided A_p condition for every α>0, or conversely a set where the weight condition holds but the set is not one-sided median porous.
read the original abstract
We introduce the notion of one-sided median porosity for subsets $E$ of $\mathbb{R}$. We prove that this condition is necessary and sufficient for the distance weight $d_E^{-\alpha}$ to belong to a one-sided Muckenhoupt $A_p$ class for some $\alpha>0$ and $1<p<\infty$. As part of the proof, we obtain new characterizations of one-sided $A_p$ weights and one-sided $\mathrm{BMO}$ functions, in terms of medians. It was recently shown that $d_E^{-\alpha}$ is a one-sided Muckenhoupt $A_1$ weight for some $\alpha>0$ if and only if $E$ is one-sided weakly porous. In this paper, we find the precise range of exponents $\alpha>0$ such that $d_E^{-\alpha}$ belongs to a one-sided $A_p$ class, both for $p=1$ and for $1<p<\infty$. In addition, we show that $E$ is median porous if and only if it is both left and right median porous, and we give an example of a one-sided median porous set which is neither median porous nor one-sided weakly porous.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper introduces one-sided median porosity for subsets E of R. It proves this condition is necessary and sufficient for the distance weight d_E^{-α} to belong to a one-sided Muckenhoupt A_p class for some α>0 and 1<p<∞. As part of the argument, new median-based characterizations of one-sided A_p weights and BMO functions are obtained. The precise range of α is determined for both the p=1 case (building on prior weak porosity results) and for 1<p<∞. It is also shown that E is median porous if and only if it is both left and right median porous, and an explicit example is given of a one-sided median porous set that is neither median porous nor one-sided weakly porous.
Significance. If the equivalences hold, the work supplies a geometric characterization linking one-sided median porosity to membership of distance weights in one-sided A_p classes, extending the recent A_1/weak-porosity equivalence. The median characterizations of A_p and BMO provide potentially useful alternative tools in one-sided harmonic analysis. The range of α and the distinguishing example clarify the relationships among porosity notions. These are solid contributions to the study of weights and function spaces on the line.
minor comments (3)
- [Abstract] The abstract states that new median characterizations are derived but does not indicate their precise form (e.g., the median condition replacing the usual integral or supremum). Adding one sentence summarizing the characterization would improve readability for readers scanning the abstract.
- [Introduction] Notation for the one-sided median operator and the precise definition of one-sided median porosity should be introduced with a displayed equation or numbered definition in the introduction or §2 to avoid any ambiguity when the reader reaches the main theorems.
- In the example distinguishing the notions, confirm that the set is constructed so that the median porosity constant is positive while the weak porosity constant is zero; a short calculation or reference to the relevant inequality would strengthen the claim.
Simulated Author's Rebuttal
We thank the referee for the positive assessment of the paper, the clear summary of its contributions, and the recommendation for minor revision. No major comments appear in the report.
Circularity Check
No significant circularity
full rationale
The paper introduces the new notion of one-sided median porosity and derives its equivalence to d_E^{-α} belonging to one-sided A_p (1<p<∞) as a fresh result, while obtaining median characterizations of A_p and BMO during the proof. The cited prior equivalence for A_1 and weak porosity serves only as background contrast and does not enter the new derivations by construction; no step reduces a claimed prediction or uniqueness theorem to a fitted parameter, self-citation chain, or renamed input. The argument is therefore self-contained against external benchmarks.
Axiom & Free-Parameter Ledger
axioms (2)
- standard math Standard properties of the median operator on intervals in R hold and interact with the distance function d_E in the expected way.
- domain assumption The one-sided Muckenhoupt A_p classes are defined via the usual one-sided maximal function or averaging operators.
invented entities (1)
-
one-sided median porosity
no independent evidence
Reference graph
Works this paper leans on
-
[1]
Quasiadditivity of Riesz capacity.Math
Hiroaki Aikawa. Quasiadditivity of Riesz capacity.Math. Scand., 69(1):15–30, 1991
1991
-
[2]
Powers of distances to lower dimen- sional sets as Muckenhoupt weights.Acta Math
Hugo Aimar, Marilina Carena, Ricardo Dur´ an, and Marisa Toschi. Powers of distances to lower dimen- sional sets as Muckenhoupt weights.Acta Math. Hungar., 143(1):119–137, 2014
2014
-
[3]
Weakly porous sets andA1 Muckenhoupt weights in spaces of homogeneous type
Hugo Aimar, Ivana G´ omez, and Ignacio G´ omez Vargas. Weakly porous sets andA1 Muckenhoupt weights in spaces of homogeneous type. 2024. Preprint athttps://arxiv.org/abs/2406.14369
-
[4]
Mart´ ın-Reyes
Hugo Aimar, Ivana G´ omez, Ignacio G´ omez Vargas, and Francisco J. Mart´ ın-Reyes. One-sided Mucken- houpt weights and one-sided weakly porous sets in R.J. Funct. Anal., 289(10):Paper No. 111110, 18, 2025
2025
-
[5]
Anderson, Juha Lehrb¨ ack, Carlos Mudarra, and Antti V
Theresa C. Anderson, Juha Lehrb¨ ack, Carlos Mudarra, and Antti V. V¨ ah¨ akangas. Weakly porous sets and MuckenhouptA p distance functions.J. Funct. Anal., 287(8):Paper No. 110558, 34, 2024
2024
-
[6]
Neugebauer, and V
David Cruz-Uribe, Christoph J. Neugebauer, and V. Olesen. The one-sided minimal operator and the one-sided reverse H¨ older inequality.Studia Math., 116(3):255–270, 1995
1995
-
[7]
Dur´ an and Fernando L´ opez Garc´ ıa
Ricardo G. Dur´ an and Fernando L´ opez Garc´ ıa. Solutions of the divergence and analysis of the Stokes equations in planar H¨ older-αdomains.Math. Models Methods Appl. Sci., 20(1):95–120, 2010. 40 A. C. GOKSAN AND I. URIARTE-TUERO
2010
-
[8]
V¨ ah¨ akangas
Bart lomiej Dyda, Lizaveta Ihnatsyeva, Juha Lehrb¨ ack, Heli Tuominen, and Antti V. V¨ ah¨ akangas. Muckenhoupt Ap-properties of distance functions and applications to Hardy-Sobolev–type inequalities. Potential Anal., 50(1):83–105, 2019
2019
-
[9]
Rubio de Francia.Weighted norm inequalities and related topics, volume 116 ofNorth-Holland Mathematics Studies
Jos´ e Garc´ ıa-Cuerva and Jos´ e L. Rubio de Francia.Weighted norm inequalities and related topics, volume 116 ofNorth-Holland Mathematics Studies. North-Holland Publishing Co., Amsterdam, 1985
1985
-
[10]
New characterizations of MuckenhouptAp distance weights for p > 1.J
Ignacio G´ omez Vargas. New characterizations of MuckenhouptAp distance weights for p > 1.J. Math. Anal. Appl., 556(1):Paper No. 130091, 27, 2026
2026
-
[11]
The imbedding theorems for weighted Sobolev spaces
Toshio Horiuchi. The imbedding theorems for weighted Sobolev spaces. II.Bull. Fac. Sci. Ibaraki Univ. Ser. A, (23):11–37, 1991
1991
-
[12]
Median porosity is quasiconformally invariant
Tero Kilpel¨ ainen and Antti V. V¨ ah¨ akangas. Median porosity is quasiconformally invariant. 2026. Preprint athttps://arxiv.org/abs/2606.05034
work page internal anchor Pith review Pith/arXiv arXiv 2026
-
[13]
American Mathematical Society, Providence, RI, 2021
Juha Kinnunen, Juha Lehrb¨ ack, and Antti V¨ ah¨ akangas.Maximal function methods for Sobolev spaces, volume 257 ofMathematical Surveys and Monographs. American Mathematical Society, Providence, RI, 2021
2021
-
[14]
Parabolic weighted norm inequalities and partial differential equations
Juha Kinnunen and Olli Saari. Parabolic weighted norm inequalities and partial differential equations. Anal. PDE, 9(7):1711–1736, 2016
2016
-
[15]
Parabolic weak porosity and parabolic Muckenhoupt distance functions
Henri Lahdelma, Kim Myyryl¨ ainen, and Antti V. V¨ ah¨ akangas. Parabolic weak porosity and parabolic Muckenhoupt distance functions. 2026. Preprint athttps://arxiv.org/abs/2604.12561
work page internal anchor Pith review Pith/arXiv arXiv 2026
-
[16]
V¨ ah¨ akangas
Juha Lehrb¨ ack and Antti V. V¨ ah¨ akangas. In between the inequalities of Sobolev and Hardy.J. Funct. Anal., 271(2):330–364, 2016
2016
-
[17]
Mart´ ın-Reyes and Alberto de la Torre
Francisco J. Mart´ ın-Reyes and Alberto de la Torre. One-sided BMO spaces.J. London Math. Soc. (2), 49(3):529–542, 1994
1994
-
[18]
Mart´ ın-Reyes, Pedro Ortega Salvador, and Alberto de la Torre
Francisco J. Mart´ ın-Reyes, Pedro Ortega Salvador, and Alberto de la Torre. Weighted inequalities for one-sided maximal functions.Trans. Amer. Math. Soc., 319(2):517–534, 1990
1990
-
[19]
Mart´ ın-Reyes, Luboˇ s Pick, and Alberto de la Torre
Francisco J. Mart´ ın-Reyes, Luboˇ s Pick, and Alberto de la Torre. A+ ∞ condition.Canad. J. Math., 45(6):1231–1244, 1993
1993
-
[20]
Weak porosity on metric measure spaces.Proc
Carlos Mudarra. Weak porosity on metric measure spaces.Proc. R. Soc. Edinb. A: Math., 2025. Advance online publication
2025
-
[21]
Marcus Pasquariello and Ignacio Uriarte-Tuero. Medians, oscillations, and distance functions. 2025. Preprint athttps://arxiv.org/abs/2507.21020
-
[22]
Medians, continuity, and vanishing oscillation.Studia Math., 213(3):227–242, 2012
Jonathan Poelhuis and Alberto Torchinsky. Medians, continuity, and vanishing oscillation.Studia Math., 213(3):227–242, 2012
2012
-
[23]
Weighted inequalities for the one-sided Hardy-Littlewood maximal functions.Trans
Eric Sawyer. Weighted inequalities for the one-sided Hardy-Littlewood maximal functions.Trans. Amer. Math. Soc., 297(1):53–61, 1986
1986
-
[24]
Porosity, dimension, and local entropies: a survey.Rev
Pablo Shmerkin. Porosity, dimension, and local entropies: a survey.Rev. Un. Mat. Argentina, 52(2):81– 103, 2011
2011
-
[25]
Springer-Verlag, Berlin, 1989
Jan-Olov Str¨ omberg and Alberto Torchinsky.Weighted Hardy spaces, volume 1381 ofLecture Notes in Mathematics. Springer-Verlag, Berlin, 1989
1989
-
[26]
Andrei V. Vasin. The limit set of a Fuchsian group and the Dynkin lemma.Zap. Nauchn. Sem. S.- Peterburg. Otdel. Mat. Inst. Steklov. (POMI), 303:89–101, 322, 2003. Department of Mathematics, University of Toronto, Toronto, Ontario, Canada Email address:a.goksan@mail.utoronto.ca Department of Mathematics, University of Toronto, Toronto, Ontario, Canada Emai...
2003
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