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Garain, P., Lindgren, E. & Tavakoli, A. (2025). Higher Hölder regularity for a subquadratic nonlocal parabolic equation. Journal of Differential Equations, 419, 253-290
Open this publication in new window or tab >>Higher Hölder regularity for a subquadratic nonlocal parabolic equation
2025 (English)In: Journal of Differential Equations, ISSN 0022-0396, E-ISSN 1090-2732, Vol. 419, p. 253-290Article in journal (Refereed) Published
Abstract [en]

In this paper, we are concerned with the Hölder regularity forsolutions of the nonlocal evolutionary equation ∂tu + (−p) su = 0. Here, (−p)s is the fractional p-Laplacian, 0 <s< 1 and 1 <p< 2. We establish Hölder regularity with explicit Hölder exponents. We also include the inhomogeneous equation with a bounded inhomogeneity. In some cases, the obtained Hölder exponents are almost sharp. Our results complement the previous results for the superquadratic case when p ≥ 2.

Place, publisher, year, edition, pages
Elsevier BV, 2025
National Category
Mathematical Analysis
Identifiers
urn:nbn:se:kth:diva-357687 (URN)10.1016/j.jde.2024.11.024 (DOI)001371728000001 ()2-s2.0-85210414430 (Scopus ID)
Note

QC 20241212

Available from: 2024-12-12 Created: 2024-12-12 Last updated: 2025-11-20Bibliographically approved
Lindgren, E. & Takahashi, J. (2025). Moving gradient singularity for the evolutionary p-Laplace equation. Journal of Elliptic and Parabolic Equations, 11(3), 2153-2164
Open this publication in new window or tab >>Moving gradient singularity for the evolutionary p-Laplace equation
2025 (English)In: Journal of Elliptic and Parabolic Equations, ISSN 2296-9020, Vol. 11, no 3, p. 2153-2164Article in journal (Refereed) Published
Abstract [en]

We consider the evolutionary p-Laplace equation in R-n x (0, infinity). For p > n, we construct a solution u with a moving gradient singularity in the sense that |del u(x, t)|-> infinity for each t as x -> (t), where : [0, infinity) -> R-n is a given curve.

Place, publisher, year, edition, pages
Springer Nature, 2025
Keywords
Evolutionary p-Laplace equation, Gradient singularity, Comparison functions
National Category
Mathematical Analysis
Identifiers
urn:nbn:se:kth:diva-364243 (URN)10.1007/s41808-025-00334-7 (DOI)001476814600001 ()2-s2.0-105003559080 (Scopus ID)
Note

QC 20260127

Available from: 2025-06-11 Created: 2025-06-11 Last updated: 2026-01-27Bibliographically approved
Hynd, R., Larson, S. & Lindgren, E. (2025). On a Hardy-Morrey inequality. Journal of Functional Analysis, 289(6), Article ID 111002.
Open this publication in new window or tab >>On a Hardy-Morrey inequality
2025 (English)In: Journal of Functional Analysis, ISSN 0022-1236, E-ISSN 1096-0783, Vol. 289, no 6, article id 111002Article in journal (Refereed) Published
Abstract [en]

Morrey's classical inequality implies the H & ouml;lder continuity of a function whose gradient is sufficiently integrable. Another consequence is the Hardy-type inequality lambda & Vert;ud Omega 1-n/p & Vert;infinity p <=integral Omega|Du|pdxfor any open set Omega & subne;Rn. This inequality is valid for functions supported in Omega and with lambda a positive constant independent of u. The crucial hypothesis is that the exponent p exceeds the dimension n. This paper aims to develop a basic theory for this inequality and the associated variational problem. In particular, we study the relationship between the geometry of Omega, sharp constants, and the existence of a nontrivial u which saturates the inequality.

Place, publisher, year, edition, pages
Elsevier BV, 2025
Keywords
Sobolev inequalities, Extremals, Sharp constants
National Category
Mathematical Analysis
Identifiers
urn:nbn:se:kth:diva-364043 (URN)10.1016/j.jfa.2025.111002 (DOI)001484868900001 ()2-s2.0-105003871285 (Scopus ID)
Note

QC 20250602

Available from: 2025-06-02 Created: 2025-06-02 Last updated: 2025-06-02Bibliographically approved
Hynd, R., Larson, S. & Lindgren, E. (2024). Decay of extremals of Morrey’s inequality. Arkiv för matematik, 62(1), 73-81
Open this publication in new window or tab >>Decay of extremals of Morrey’s inequality
2024 (English)In: Arkiv för matematik, ISSN 0004-2080, E-ISSN 1871-2487, Vol. 62, no 1, p. 73-81Article in journal (Refereed) Published
Abstract [en]

We study the decay (at infinity) of extremals of Morrey’s inequality in Rn. These are functions satisfying (Formula Presented) where p>n and C(p, n) is the optimal constant in Morrey’s inequality. We prove that if n≥2 then any extremal has a power decay of order β for any (Formula Presented).

Place, publisher, year, edition, pages
International Press, Inc., 2024
Keywords
decay at infinity, Morrey’s inequality, the p-Laplace equation
National Category
Mathematical Analysis
Identifiers
urn:nbn:se:kth:diva-348745 (URN)10.4310/ARKIV.2024.v62.n1.a4 (DOI)001301077000004 ()2-s2.0-85196254755 (Scopus ID)
Note

QC 20241001

Available from: 2024-06-27 Created: 2024-06-27 Last updated: 2024-10-01Bibliographically approved
Garain, P. & Lindgren, E. (2024). Higher Hölder regularity for the fractional p-Laplace equation in the subquadratic case. Mathematische Annalen, 390(4), 5753-5792
Open this publication in new window or tab >>Higher Hölder regularity for the fractional p-Laplace equation in the subquadratic case
2024 (English)In: Mathematische Annalen, ISSN 0025-5831, E-ISSN 1432-1807, Vol. 390, no 4, p. 5753-5792Article in journal (Refereed) Published
Abstract [en]

We study the fractional p-Laplace equation (−p) s u = 0 for 0 < s < 1 and in the subquadratic case 1 < p < 2. We provide Hölder estimates with an explicit Hölder exponent. The inhomogeneous equation is also treated and there the exponent obtained is almost sharp for a certain range of parameters. Our results complement the previous results for the superquadratic case when p ≥ 2. The arguments are based on a careful Moser-type iteration and a perturbation argument.

Place, publisher, year, edition, pages
Springer Nature, 2024
Keywords
35B65, 35J75, 35R09
National Category
Mathematical Analysis
Identifiers
urn:nbn:se:kth:diva-366319 (URN)10.1007/s00208-024-02891-z (DOI)001234601500001 ()2-s2.0-85194258395 (Scopus ID)
Note

QC 20250707

Available from: 2025-07-07 Created: 2025-07-07 Last updated: 2025-07-07Bibliographically approved
del Teso, F. & Lindgren, E. (2023). Finite difference schemes for the parabolic p-Laplace equation. SeMA Journal, 80(4), 527-547
Open this publication in new window or tab >>Finite difference schemes for the parabolic p-Laplace equation
2023 (English)In: SeMA Journal, ISSN 2254-3902, Vol. 80, no 4, p. 527-547Article in journal (Refereed) Published
Abstract [en]

We propose a new finite difference scheme for the degenerate parabolic equation ∂tu-div(|∇u|p-2∇u)=f,p≥2.Under the assumption that the data is Hölder continuous, we establish the convergence of the explicit-in-time scheme for the Cauchy problem provided a suitable stability type CFL-condition. An important advantage of our approach, is that the CFL-condition makes use of the regularity provided by the scheme to reduce the computational cost. In particular, for Lipschitz data, the CFL-condition is of the same order as for the heat equation and independent of p.

Place, publisher, year, edition, pages
Springer Nature, 2023
Keywords
Explicit scheme, Finite differences, Mean value property, p-Laplacian, Viscosity solutions
National Category
Computational Mathematics
Identifiers
urn:nbn:se:kth:diva-335771 (URN)10.1007/s40324-022-00316-y (DOI)001572866300007 ()2-s2.0-85140333018 (Scopus ID)
Note

QC 20251218

Available from: 2023-09-08 Created: 2023-09-08 Last updated: 2025-12-18Bibliographically approved
Garain, P. & Lindgren, E. (2023). Higher Holder regularity for mixed local and nonlocal degenerate elliptic equations. Calculus of Variations and Partial Differential Equations, 62(2), Article ID 67.
Open this publication in new window or tab >>Higher Holder regularity for mixed local and nonlocal degenerate elliptic equations
2023 (English)In: Calculus of Variations and Partial Differential Equations, ISSN 0944-2669, E-ISSN 1432-0835, Vol. 62, no 2, article id 67Article in journal (Refereed) Published
Abstract [en]

We consider equations involving a combination of local and nonlocal degenerate p-Laplace operators. The main contribution of the paper is almost Lipschitz regularity for the homogeneous equation and Holder continuity with an explicit Holder exponent in the general case. For certain parameters, our results also imply Holder continuity of the gradient. In addition, we establish existence, uniqueness and local boundedness. The approach is based on an iteration in the spirit of Moser combined with an approximation method.

Place, publisher, year, edition, pages
Springer Nature, 2023
Keywords
35B65, 35D30, 35J70, 35R09, 35R11
National Category
Mathematics
Identifiers
urn:nbn:se:kth:diva-325598 (URN)10.1007/s00526-022-02401-6 (DOI)000910669200009 ()2-s2.0-85145690330 (Scopus ID)
Note

QC 20230412

Available from: 2023-04-12 Created: 2023-04-12 Last updated: 2023-04-12Bibliographically approved
Brustad, K. K., Lindgren, E. & Lindqvist, P. (2023). The infinity-Laplacian in smooth convex domains and in a square. MATHEMATICS IN ENGINEERING, 5(4), 1-16
Open this publication in new window or tab >>The infinity-Laplacian in smooth convex domains and in a square
2023 (English)In: MATHEMATICS IN ENGINEERING, ISSN 2640-3501, Vol. 5, no 4, p. 1-16Article in journal (Refereed) Published
Abstract [en]

We extend some theorems for the infinity-ground state and for the infinity-potential, known for convex polygons, to other domains in the plane, by applying Alexandroff's method to the curved boundary. A recent explicit solution disproves a conjecture.

Place, publisher, year, edition, pages
American Institute of Mathematical Sciences (AIMS), 2023
Keywords
the infinity-Laplace operator, nonlinear eigenvalue problem, convex plane domains, gradient flow, Alexandroff?s moving plane
National Category
Mathematical Analysis
Identifiers
urn:nbn:se:kth:diva-326049 (URN)10.3934/mine.2023080 (DOI)000957586600001 ()2-s2.0-85154531608 (Scopus ID)
Note

QC 20230425

Available from: 2023-04-25 Created: 2023-04-25 Last updated: 2023-06-08Bibliographically approved
Brasco, L. & Lindgren, E. (2023). Uniqueness of extremals for some sharp Poincaré-Sobolev constants. Transactions of the American Mathematical Society, 376(5), 3541-3584
Open this publication in new window or tab >>Uniqueness of extremals for some sharp Poincaré-Sobolev constants
2023 (English)In: Transactions of the American Mathematical Society, ISSN 0002-9947, E-ISSN 1088-6850, Vol. 376, no 5, p. 3541-3584Article in journal (Refereed) Published
Abstract [en]

We study the sharp constant for the embedding of W01,p(Ω) into Lq(Ω), in the case 2 < p < q. We prove that for smooth connected sets, when q > p and q is sufficiently close to p, extremal functions attaining the sharp constant are unique, up to a multiplicative constant. This in turn gives the uniqueness of solutions with minimal energy to the Lane-Emden equation, with super-homogeneous right-hand side. The result is achieved by suitably adapting a linearization argument due to C.-S. Lin. We rely on some fine estimates for solutions of p−Laplace–type equations by L. Damascelli and B. Sciunzi.

Place, publisher, year, edition, pages
American Mathematical Society (AMS), 2023
Keywords
Lane-Emden equation, nonlinear eigenvalue problems, Poincaré-Sobolev constants, p−Laplacian, weighted Sobolev spaces
National Category
Mathematical Analysis
Identifiers
urn:nbn:se:kth:diva-331579 (URN)10.1090/tran/8838 (DOI)000932677400001 ()2-s2.0-85158985106 (Scopus ID)
Note

QC 20230711

Available from: 2023-07-11 Created: 2023-07-11 Last updated: 2023-09-05Bibliographically approved
Korvenpaa, J., Kuusi, T. & Lindgren, E. (2019). Equivalence of solutions to fractional p-Laplace type equations. Journal des Mathématiques Pures et Appliquées, 132, 1-26
Open this publication in new window or tab >>Equivalence of solutions to fractional p-Laplace type equations
2019 (English)In: Journal des Mathématiques Pures et Appliquées, ISSN 0021-7824, E-ISSN 1776-3371, Vol. 132, p. 1-26Article in journal (Refereed) Published
Abstract [en]

In this paper, we study different notions of solutions of nonlocal and nonlinear equations of fractional p-Laplace type P.V. integral(Rn)vertical bar u(x) - u(y)vertical bar(p-2)(u(x) - u(y))/vertical bar x-y vertical bar(n+sp) dy = 0. Solutions are defined via integration by parts with test functions, as viscosity solutions or via comparison. Our main result states that for bounded solutions, the three different notions coincide. (C) 2017 Elsevier Masson SAS. All rights reserved.

Place, publisher, year, edition, pages
ELSEVIER, 2019
Keywords
Nonlocal operators, Fractional Sobolev spaces, Fractional p-Laplacian, Viscosity solutions
National Category
Mathematics
Identifiers
urn:nbn:se:kth:diva-266291 (URN)10.1016/j.matpur.2017.10.004 (DOI)000500376300001 ()2-s2.0-85074411859 (Scopus ID)
Note

QC 20200107

Available from: 2020-01-07 Created: 2020-01-07 Last updated: 2022-06-26Bibliographically approved
Projects
Nonlinear eigenvalue problems and regularity theory for nonlocal nonlinear equations [2017-03736_VR]; Uppsala University
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4309-9242

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