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arxiv: 2604.07489 · v1 · submitted 2026-04-08 · 🧮 math.AP

Lipschitz regularity for fractional p-Laplacian with coercive gradients

Pith reviewed 2026-05-10 17:11 UTC · model grok-4.3

classification 🧮 math.AP
keywords fractional p-Laplacianviscosity solutionsLipschitz regularitycoercive gradientnonlocal equationsHölder continuitybounded solutionsLiouville theorem
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The pith

Viscosity solutions to fractional p-Laplacian equations with coercive gradient nonlinearities are locally Lipschitz continuous under bounds on p.

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

The paper studies a nonlinear nonlocal equation combining the fractional p-Laplacian operator with a coercive term that depends on the gradient and a Lipschitz continuous right-hand side. It proves that every viscosity solution is locally Lipschitz continuous when p lies in the interval (1, 2/(1-s)) union (1, m+1). The work also obtains Hölder continuity for subsolutions and shows that the homogeneous equation with position-independent nonlinearity admits only the zero function among bounded solutions, for arbitrary m and p greater than 1. These regularity and uniqueness statements matter because they supply quantitative control on solutions without assuming smoothness in advance.

Core claim

Any viscosity solution u to the equation (-Δ_p)^s u(x) + H(x, ∇u) = f is locally Lipschitz continuous when p belongs to (1, 2/(1-s)) ∪ (1, m+1), with f Lipschitz continuous and H coercive. Subsolutions satisfy Hölder continuity, and when f vanishes and H does not depend on x the only bounded solution is identically zero for all m, p > 1.

What carries the argument

Viscosity solution framework for the fractional p-Laplacian with coercive gradient perturbation, relying on comparison principles and oscillation estimates to control the gradient.

If this is right

  • Solutions to the equation acquire local Lipschitz regularity directly from the structure without additional assumptions on u.
  • In the homogeneous case with x-independent H the equation forces every bounded solution to be zero.
  • Subsolutions satisfy interior Hölder continuity estimates that hold independently of the full Lipschitz conclusion.
  • The admissible range for p enlarges or shrinks according to the fractional order s and the growth exponent m of H.

Where Pith is reading between the lines

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

  • The same comparison techniques might adapt to other nonlocal operators that possess a similar coercivity structure in the gradient term.
  • The Liouville-type result for bounded solutions suggests possible extensions to entire-space problems or long-time asymptotics.
  • Relaxing coercivity of H would likely produce counterexamples to Lipschitz regularity, testing the necessity of that hypothesis.

Load-bearing premise

The gradient term H must be coercive, the right-hand side f must be Lipschitz continuous, and p must lie inside the stated range relative to s and m so that the comparison and oscillation arguments close.

What would settle it

Construction of a non-Lipschitz viscosity solution for some p outside the given intervals, or for a non-coercive H, would disprove the Lipschitz claim.

read the original abstract

In this article, we study nonlinear nonlocal equations with coercive gradient nonlinearity of the form \[ (-\Delta_p)^s u(x) + H(x, \nabla u) = f, \] where $f$ is Lipschitz continuous. We show that any viscosity solution $u$ is locally Lipschitz continuous, provided \[ p \in \left(1, \frac{2}{1-s}\right) \cup (1, m+1). \] We also establish H\"older continuity of subsolutions. Furthermore, in the case $f=0$ and $H$ is independent of $x$, we prove that the equation admits only the trivial solution in the class of bounded solutions, for all $m, p \in (1,\infty)$.

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 / 3 minor

Summary. The manuscript establishes local Lipschitz continuity for viscosity solutions of the nonlocal equation (-Δ_p)^s u + H(x, ∇u) = f, where f is Lipschitz continuous, under the explicit restriction p ∈ (1, 2/(1-s)) ∪ (1, m+1). It further proves Hölder continuity for subsolutions and shows that the homogeneous problem (f = 0, H independent of x) admits only the trivial bounded solution for all m, p > 1.

Significance. If the proofs are correct, the results extend regularity theory for fractional p-Laplacian equations to include coercive gradient nonlinearities, with explicit parameter ranges that indicate where comparison and oscillation estimates close. The uniqueness statement for the homogeneous case is notably broad, holding without further restrictions on m or p. These contributions would be useful for analyzing nonlocal equations with nonlinear drift terms.

minor comments (3)
  1. The abstract and introduction state the parameter restrictions clearly, but a brief remark on why the estimates fail for p outside the given range would improve readability.
  2. The definition of viscosity solutions should explicitly address how the nonlocal tail is controlled in the comparison principle arguments.
  3. Notation for the fractional p-Laplacian operator and the coercivity assumption on H could be recalled in the statement of the main theorems for self-contained reading.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for the positive assessment of our work and the recommendation for minor revision. No specific major comments appear in the report.

Circularity Check

0 steps flagged

No significant circularity; derivation self-contained via comparison principles

full rationale

The paper establishes Lipschitz regularity for viscosity solutions of the nonlocal equation via comparison principles and oscillation estimates that close under the stated restrictions on p relative to s and m. These restrictions are explicitly required for the estimates to hold and do not reduce any claimed result to a fitted parameter or self-defined quantity. The uniqueness result for the homogeneous case follows directly from the coercivity assumption on H without invoking self-citations as load-bearing premises. No step equates a prediction to its input by construction, and the central claims remain independent of any prior self-citation chain.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The central claims rest on the standard definition of viscosity solutions for nonlocal operators, the coercivity assumption on H, and the Lipschitz regularity of f; no free parameters or new entities are introduced.

axioms (2)
  • domain assumption Viscosity solution definition for the fractional p-Laplacian with gradient nonlinearity
    Invoked throughout the abstract to frame the regularity statements.
  • domain assumption Coercivity of the gradient term H(x, ∇u)
    Required for the comparison principle that yields the Lipschitz bound.

pith-pipeline@v0.9.0 · 5426 in / 1378 out tokens · 42780 ms · 2026-05-10T17:11:17.363021+00:00 · methodology

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Reference graph

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