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arxiv: 1907.03659 · v1 · pith:RZRSJUUQnew · submitted 2019-07-08 · 🧮 math.AP

Some isoperimetric inequalities with respect to monomial weights

Pith reviewed 2026-05-25 00:58 UTC · model grok-4.3

classification 🧮 math.AP
keywords isoperimetric inequalitymonomial weightsweighted perimeterupper half-planeCheeger constanteigenvalue bound
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The pith

Among smooth sets in the upper half-plane with fixed y^β measure, the y^α weighted perimeter is minimized by an explicit y-axis symmetric set.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper establishes an isoperimetric inequality on the upper half-plane using monomial weights that are powers of the vertical coordinate. For sets with a fixed value of the weighted area integral involving y to the power β, it identifies the sets that minimize the weighted perimeter integral involving y to the power α. The minimizing sets are proved to be smooth and symmetric with respect to the y-axis under explicit restrictions on the two exponents. The same construction supplies a bound on the associated weighted Cheeger constant and a lower bound on the first eigenvalue of related nonlinear eigenvalue problems.

Core claim

We show that, among all smooth sets Ω in R²₊ with fixed weighted measure ∬_Ω y^β dx dy, the weighted perimeter ∫_{∂Ω} y^α ds achieves its minimum for a smooth set which is symmetric w.r.t. the y-axis, and is explicitly given.

What carries the argument

The explicit y-axis symmetric minimizer of the weighted perimeter under the weighted area constraint.

If this is right

  • The minimizer is smooth and symmetric with respect to the y-axis.
  • The construction yields an estimate for the weighted Cheeger constant.
  • A lower bound follows for the first eigenvalue of a class of nonlinear problems.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The explicit form of the minimizer permits direct calculation of the optimal isoperimetric ratio under the stated exponent conditions.
  • The symmetry conclusion may indicate how the same weighted perimeter behaves when the domain is restricted further or when the weights are applied in related variational problems.

Load-bearing premise

The result requires the sets to be smooth and the exponents to satisfy 0 ≤ α < β + 1 together with β ≤ 2α.

What would settle it

A smooth set in the upper half-plane whose weighted area equals that of the claimed minimizer but whose weighted perimeter is strictly smaller would falsify the minimality statement.

Figures

Figures reproduced from arXiv: 1907.03659 by Angelo Alvino, Anna Mercaldo, Francesco Chiacchio, Friedemann Brock, Maria Rosaria Posteraro.

Figure 1
Figure 1. Figure 1: Isoperimetric sets for different values of α and β 2. Isoperimetric inequality in the upper half plane Let R 2 + := {(x, y) ∈ R 2 : y > 0}. Throughout this paper, we assume that α, β ∈ R and (2.1) β + 1 > 0 and α ≥ 0. If Ω ⊂ R 2 + is measurable, we set (2.2) Ω(y) := {x ∈ R : (x, y) ∈ Ω}, (y ∈ R+), Ω 0 (2.3) := {y ∈ R+ : Ω(y) 6= ∅}. Further, we define the weighted area of Ω by Aβ(Ω) := Z Z Ω y β dxdy, and t… view at source ↗
read the original abstract

We solve a class of isoperimetric problems on $\mathbb{R}^2_+ :=\left\{ (x,y)\in \mathbb{R} ^2 : y>0 \right\}$ with respect to monomial weights. Let $\alpha $ and $\beta $ be real numbers such that $0\le \alpha <\beta+1$, $\beta\le 2 \alpha$. We show that, among all smooth sets $\Omega$ in $\mathbb{R} ^2_+$ with fixed weighted measure $\iint_{\Omega } y^{\beta} dxdy$, the weighted perimeter $\int_{\partial \Omega } y^\alpha \, ds$ achieves its minimum for a smooth set which is symmetric w.r.t. to the $y$--axis, and is explicitly given. Our results also imply an estimate of a weighted Cheeger constant and a lower bound for the first eigenvalue of a class of nonlinear problems.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

0 major / 2 minor

Summary. The manuscript solves a class of weighted isoperimetric problems in the upper half-plane R²₊. For real parameters satisfying 0 ≤ α < β + 1 and β ≤ 2α, it asserts that among all smooth sets Ω ⊂ R²₊ with fixed weighted measure ∬_Ω y^β dx dy, the weighted perimeter ∫_{∂Ω} y^α ds attains its minimum at an explicitly described smooth set that is symmetric with respect to the y-axis. The results are also used to bound the weighted Cheeger constant and to obtain a lower bound on the first eigenvalue of an associated class of nonlinear eigenvalue problems.

Significance. If the central claim holds, the explicit identification of the minimizer supplies a concrete, verifiable example of equality in a weighted isoperimetric inequality under monomial weights. The parameter restrictions are presented as the natural regime in which a smooth closed comparison curve exists, and the consequences for the Cheeger constant and nonlinear eigenvalues extend the utility of the result beyond the pure isoperimetric statement.

minor comments (2)
  1. The abstract states that the minimizer is 'explicitly given' but does not display the explicit form or the associated curvature equation; adding the explicit expression (or at least the ODE it satisfies) to the abstract or the first paragraph of the introduction would improve immediate readability.
  2. The restriction to smooth sets is stated clearly, yet the introduction could briefly indicate whether the same explicit set remains a minimizer (or at least a stationary point) in a larger class such as sets of finite weighted perimeter.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for the positive assessment and recommendation of minor revision. The referee's summary correctly reflects the scope and consequences of the results. No major comments appear in the report, so we have no points requiring rebuttal or clarification at this stage. Any minor suggestions will be incorporated in the revised manuscript.

Circularity Check

0 steps flagged

No significant circularity detected

full rationale

The paper proves a direct minimization theorem: among smooth sets of fixed weighted measure ∬_Ω y^β dx dy, the weighted perimeter ∫_{∂Ω} y^α ds is minimized by an explicitly described y-axis symmetric set, under the stated restrictions 0 ≤ α < β+1 and β ≤ 2α. This is a self-contained existence and characterization result in the calculus of variations; the minimizer is constructed independently (via the associated weighted curvature problem) rather than being defined in terms of the perimeter itself. No steps reduce by construction to fitted inputs, self-citations, or ansatzes smuggled from prior work by the same authors. The result stands as an independent theorem with explicit assumptions and does not rely on renaming known patterns or load-bearing self-references.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The abstract invokes standard existence and regularity results from the calculus of variations for isoperimetric problems but introduces no free parameters, no new entities, and no ad-hoc axioms beyond the usual background of geometric measure theory.

axioms (1)
  • domain assumption Existence of minimizers in the class of smooth sets for the weighted isoperimetric problem under the given parameter restrictions.
    The claim is stated only for smooth sets and relies on the parameters ensuring the problem is well-posed.

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Works this paper leans on

41 extracted references · 41 canonical work pages · 2 internal anchors

  1. [1]

    Abreu, L.G

    E. Abreu, L.G. Fernandes , On existence and nonexistence of isoperimetric inequalities with different monomial weights. arXiv:1904.01441v2, 11 Apr 2019

  2. [2]

    Alvino, F

    A. Alvino, F. Brock, F. Chiacchio, A. Mercaldo, M.R. Posteraro , Some isoperi- metric inequalities on RN with respect to weights|x|α, J. Math. Anal. Appl. 451, no. 1, (2017), 280–318

  3. [3]

    Alvino, F

    A. Alvino, F. Brock, F. Chiacchio, A. Mercaldo, M.R. Posteraro , On weighted isoperimetric inequalities with non-radial densities (2018), Appl. Anal. , to appear doi.org/10.1080/00036811.2018.1506106

  4. [4]

    Alvino, F

    A. Alvino, F. Brock, F. Chiacchio, A. Mercaldo, M.R. Posteraro, The isoperimet- ric problem for a class of non-radial weights and applications (2018), J. Differential Equations, to appear

  5. [5]

    Bayle, A

    V. Bayle, A. Ca ˜nete, F. Morgan, C. Rosales , On the isoperimetric problem in Eu- clidean space with density. Calc. Var. PDE 31 (2008), 27–46

  6. [6]

    Betta, F

    M.F. Betta, F. Brock, A. Mercaldo, M.R. Posteraro , A weighted isoperimetric inequality and applications to symmetrization. J. Inequal. Appl. 4 (1999), no. 3, 215-240

  7. [7]

    Betta, F

    M.F. Betta, F. Brock, A. Mercaldo, M.R. Posteraro , Weighted isoperimetric in- equalities on RN and applications to rearrangements. Math. Nachr. 281 (2008), no. 4, 466– 498

  8. [8]

    Boyer, B

    W. Boyer, B. Brown, G. Chambers, A. Loving, S. Tammen , Isoperimetric regions in Rn with density rp, Anal. Geom. Metr. Spaces 4 (2016), 236–265

  9. [9]

    Brandolini, F

    B. Brandolini, F. Della Pietra, C. Nitsch, C. Trombetti , Symmetry breaking in a constrained Cheeger type isoperimetric inequality. (English summary) ESAIM Control Optim. Calc. Var. 21 (2015), 359–371

  10. [10]

    Brock, F

    F. Brock, F. Chiacchio, A. Mercaldo, A weighted isoperimetric inequality in an orthant. Potential Anal. 41 (2012), 171–186

  11. [11]

    Brock, A

    F. Brock, A. Mercaldo, M.R. Posteraro, On isoperimetric inequalities with respect to infinite measures. Revista Matem´ atica Iberoamericana29 (2013), 665–690

  12. [12]

    Bucur, I

    D. Bucur, I. Fragal `a, Proof of the honeycomb asymptotics for optimal Cheeger clusters. Adv. Math. 350 (2019), 97–129

  13. [13]

    Bucur, I

    D. Bucur, I. Fragal `a, A Faber-Krahn inequality for the Cheeger constant of N-gons. J. Geom. Anal. 26 (2016), 88–117

  14. [14]

    Cabre, X

    X. Cabre, X. Ros-Oton, Sobolev and isoperimetric inequalities with monomial weights. J. Differential Equations 255 (2013), 4312–4336

  15. [15]

    Cabre, X

    X. Cabre, X. Ros-Oton, J. Serra, Euclidean balls solve some isoperimetric problems with nonradial weights. C. R. Math. Acad. Sci. Paris 350 (2012), 945–947

  16. [16]

    Ca˜nete, M

    A. Ca˜nete, M. Miranda Jr., D. Vittone , Some isoperimetric problems in planes with density. J. Geom. Anal. 20 (2010), no.2, 243–290

  17. [17]

    Carroll, A

    T. Carroll, A. Jacob, C. Quinn, R. Walters, The isoperimetric problem on planes with density. Bull. Aust. Math. Soc. 78 (2008), no.2, 177–197. SOME ISOPERIMETRIC INEQUALITIES WITH RESPECT TO MONOMIAL WEIGHTS 29

  18. [18]

    Caselles, M

    V. Caselles, M. Miranda jr, M. Novaga , Total variation and Cheeger sets in Gauss space. J. Funct. Anal. 259 (2010), 1491–1516

  19. [19]

    Castro, Hardy-Sobolev inequalities with monomial weights

    H. Castro, Hardy-Sobolev inequalities with monomial weights. Ann. Mat. Pura Appl. (4) 196 (2017), no. 2, 579–598

  20. [20]

    G. R. Chambers, Proof of the Log-Convex Density Conjecture, arXiv:1311.4012v3, to appear in: Journal of the European Mathematics Society

  21. [21]

    Cheeger, A lower bound for the smallest eigenvalue of the Laplacian,Problems in analysis: A symposium in honor of Salomon Bochner (1970), 195–199

    J. Cheeger, A lower bound for the smallest eigenvalue of the Laplacian,Problems in analysis: A symposium in honor of Salomon Bochner (1970), 195–199

  22. [22]

    Csat´o, An isoperimetric problem with density and the Hardy Sobolev inequality in R2, Differential Integral Equations 28 (2015), no

    G. Csat´o, An isoperimetric problem with density and the Hardy Sobolev inequality in R2, Differential Integral Equations 28 (2015), no. 9-10, 971-988

  23. [23]

    Dahlberg, A

    J. Dahlberg, A. Dubbs, E. Newkirk, H. Tran , Isoperimetric regions in the plane with densityrp, New York J. Math. 16 (2010), 31-51

  24. [24]

    De Philippis, G

    G. De Philippis, G. Franzina, A. Pratelli, Existence of isoperimetric sets with densities ”converging from below” on RN. J. Geom. Anal. 27 (2017), 1086–1105

  25. [25]

    Balls Isoperimetric in $\mathbb{R}^n$ with Volume and Perimeter Densities $r^m$ and $r^k$

    L. Di Giosia, J. Habib, L. Kenigsberg, D. Pittman, W. Zhu , Balls Isoperimetric in Rn with Volume and Perimeter Densities rm and rk. (2019), arXiv:1610.05830v2

  26. [26]

    A. Diaz, N. Harman, S. Howe, D. Thompson Isoperimetric problems in sectors with density. Adv. Geom. 12 (2012), 589-619

  27. [27]

    Gurka, B

    P. Gurka, B. Opic , Continuous and compact imbeddings of weighted Sobolev spaces II , Czechoslovak Math. J. 39 (113) (1989), no. 1, 78–94

  28. [28]

    Harman, S

    N. Harman, S. Howe, F. Morgan , Steiner and Schwarz symmetrization in warped prod- ucts and fiber bundles with density. Rev. Mat. Iberoamericana 27 (2011), no. 3, 909–918

  29. [29]

    Howe, The Log-Convex Density Conjecture and vertical surface area in warped products

    S. Howe, The Log-Convex Density Conjecture and vertical surface area in warped products. Adv. Geom. 15 (2015), 455-468

  30. [30]

    Ionescu, T

    I.R. Ionescu, T. Lachand-Robert , Generalized Cheeger sets related to landslides. Calc. Var. Partial Differential Equations 23 (2005), 227–249

  31. [31]

    Kawohl, V

    B. Kawohl, V. Fridman , Isoperimetric estimates for the first eigenvalue of the p-Laplace operator and the Cheeger constant. Comment. Math. Univ. Carolin. 44 (2003), no. 4, 659–667

  32. [32]

    Kolesnikov, R.I

    A.V. Kolesnikov, R.I. Zhdanov , On isoperimetric sets of radially symmetric measures. Concentration, functional inequalities and isoperimetry, 123-154, Contemp. Math. 545, Amer. Math. Soc., Providence, RI, 2011

  33. [33]

    Maderna, S

    C. Maderna, S. Salsa , Sharp estimates for solutions to a certain type of singular elliptic boundary value problems in two dimensions. Applicable Analysis 12 (1981), no.4, 307–321

  34. [34]

    Maz’ja, Lectures on isoperimetric and isocapacitary inequalities in the theory of Sobolev spaces

    V. Maz’ja, Lectures on isoperimetric and isocapacitary inequalities in the theory of Sobolev spaces. Heat kernels and analysis on manifolds, graphs, and metric spaces (Paris, 2002), 307– 340, Contemp. Math. 338, Amer. Math. Soc., Providence, RI, 2003

  35. [35]

    Maz’ja, T

    V. Maz’ja, T. Shaposhnikova, A collection of sharp dilation invariant integral inequalities for differentiable functions, Sobolev spaces in mathematics I , 223-247. Int. Math. Ser. (N. Y.) 8 Springer, 2009

  36. [36]

    Morgan, Manifolds with density

    F. Morgan, Manifolds with density. Notices Amer. Math. Soc. 52 (2005), no.8, 853–858

  37. [37]

    Morgan, The Log-Convex Density Conjecture

    F. Morgan, The Log-Convex Density Conjecture. Contemporary Mathematics 545 (2011), 209–211

  38. [38]

    Morgan, A

    F. Morgan, A. Pratelli , Existence of isoperimetric regions in RN with density. Ann. Global Anal. Geom. 43 (2013), 331–365

  39. [39]

    Parini, An introduction to the Cheeger problem

    E. Parini, An introduction to the Cheeger problem. Surv. Math. Appl. 6 (2011), 9–21

  40. [40]

    Pratelli, G

    A. Pratelli, G. Saracco , On the isoperimetric problem with double density. Nonlinear Anal. 177 (2018), 733–752. 30 A. AL VINO, F. BROCK, F. CHIACCHIO, A. MERCALDO, AND M.R. POSTERARO

  41. [41]

    Saracco, Weighted Cheeger sets are domains of isoperimetry

    G. Saracco, Weighted Cheeger sets are domains of isoperimetry. Manuscripta Math. 156 (2018), no. 3-4, 371–381