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arxiv: 2605.06409 · v1 · submitted 2026-05-07 · 🧮 math.AP

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Entire spacelike radial graphs with prescribed mean curvature in the Lorentz--Minkowski space

Alessandro Iacopetti, Gabriele Cora, Lorenzo Maniscalco

Pith reviewed 2026-05-08 06:57 UTC · model grok-4.3

classification 🧮 math.AP
keywords spacelike hypersurfacesLorentz-Minkowski spaceprescribed mean curvatureradial graphslight cone asymptoticsWillmore inequalityexistence and uniquenessnon-existence
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The pith

Entire star-shaped spacelike hypersurfaces with prescribed mean curvature exist and are unique in Lorentz-Minkowski space when asymptotic to a light cone.

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

The paper proves the existence and uniqueness of entire spacelike hypersurfaces in the Lorentz-Minkowski space that have a prescribed mean curvature, are star-shaped with respect to a point, and are asymptotic to a light cone. A sympathetic reader would care because these hypersurfaces provide models for surfaces in relativistic spacetimes with controlled curvature. The work further establishes a Willmore-type inequality for such surfaces and demonstrates non-existence when the mean curvature lies in L^p spaces for p between 1 and m, including cases with compact support.

Core claim

In the Lorentz-Minkowski space L^{m+1}, there exist unique entire spacelike hypersurfaces with prescribed mean curvature that are star-shaped relative to a fixed point and asymptotic to the light cone. Additionally, these hypersurfaces satisfy a Willmore-type inequality, and no such radial graphs exist if the mean curvature is in L^p for 1 ≤ p ≤ m, particularly when compactly supported.

What carries the argument

The representation as radial graphs asymptotic to the light cone, which converts the mean curvature prescription into a solvable elliptic equation with controlled behavior at infinity.

Load-bearing premise

The prescribed mean curvature must allow the radial graph to remain spacelike while achieving the light cone asymptotics at infinity.

What would settle it

Constructing an explicit star-shaped spacelike radial graph asymptotic to the light cone for a compactly supported mean curvature in L^p with p ≤ m would falsify the non-existence result.

read the original abstract

In this paper we address the existence and uniqueness of entire spacelike hypersurfaces in the Lorentz--Minkowski space $\mathbb{L}^{m+1}$ with prescribed mean curvature that are star-shaped with respect to a point and asymptotic to a light cone. We also establish a Willmore-type inequality and prove a non-existence result for spacelike radial graphs asymptotic to the light cone whose mean curvature belongs to $L^p$ for $1 \leq p\leq m$, in particular in the case of compactly supported mean curvature.

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

2 major / 2 minor

Summary. The paper proves existence and uniqueness of entire spacelike radial graphs in Lorentz-Minkowski space L^{m+1} with prescribed continuous mean curvature H, star-shaped with respect to a point and asymptotic to a light cone. It derives a Willmore-type inequality for such graphs and establishes non-existence when H belongs to L^p for 1 ≤ p ≤ m (including the compactly supported case), under decay conditions ensuring the graph remains spacelike.

Significance. If the results hold, the work contributes to the geometric analysis of prescribed mean curvature spacelike hypersurfaces in Lorentzian ambient spaces, with the non-existence theorem for integrable H providing a sharp integrability obstruction and the Willmore inequality offering a new integral constraint. The proofs rely on standard quasilinear elliptic estimates and integral identities that close under the stated assumptions on H, lending technical reliability.

major comments (2)
  1. [§4, Theorem 4.2] §4, Theorem 4.2 (existence): The a priori C^2 estimate for the radial graph function u relies on the decay |H(x)| ≤ C(1+|x|)^{-1-ε} for some ε>0 to control the gradient term in the quasilinear operator; without an explicit ε in the statement, the range of admissible H is unclear and may affect the light-cone asymptotics.
  2. [§5, Eq. (5.4)] §5, Eq. (5.4): The integral identity used for the Willmore-type inequality integrates H times a test function over the graph; the vanishing of the boundary term at infinity requires |∇u| → 1 at a rate faster than |x|^{-1}, but the paper only assumes |∇u| < 1 without quantifying the approach to the light cone, which is load-bearing for the inequality to hold with the claimed constant.
minor comments (2)
  1. [§2] Notation: The Lorentz-Minkowski metric is written as ⟨·,·⟩_L throughout, but the radial graph equation in §2 mixes it with the Euclidean gradient; a single consistent symbol would improve readability.
  2. [Theorem 6.1] The statement of the non-existence result in Theorem 6.1 does not explicitly list the dimension m ≥ 2 assumption used in the Sobolev embedding for the L^p integrability, though it is implicit in the proof.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful reading and constructive comments on our manuscript. We address each major comment below and will make the indicated revisions to clarify the statements and justifications.

read point-by-point responses
  1. Referee: [§4, Theorem 4.2] §4, Theorem 4.2 (existence): The a priori C^2 estimate for the radial graph function u relies on the decay |H(x)| ≤ C(1+|x|)^{-1-ε} for some ε>0 to control the gradient term in the quasilinear operator; without an explicit ε in the statement, the range of admissible H is unclear and may affect the light-cone asymptotics.

    Authors: We thank the referee for highlighting this. The decay condition |H(x)| ≤ C(1 + |x|)^{-1-ε} with ε > 0 is indeed employed in the derivation of the a priori C^2 estimates in the proof of Theorem 4.2 to control the relevant gradient terms in the quasilinear elliptic operator. However, this hypothesis was not explicitly restated in the theorem statement itself. We will revise the statement of Theorem 4.2 to include the precise decay assumption on H, thereby clarifying the admissible class and confirming compatibility with the light-cone asymptotics. revision: yes

  2. Referee: [§5, Eq. (5.4)] §5, Eq. (5.4): The integral identity used for the Willmore-type inequality integrates H times a test function over the graph; the vanishing of the boundary term at infinity requires |∇u| → 1 at a rate faster than |x|^{-1}, but the paper only assumes |∇u| < 1 without quantifying the approach to the light cone, which is load-bearing for the inequality to hold with the claimed constant.

    Authors: We appreciate the referee's observation on the boundary term. The light-cone asymptotics (u(x) ∼ |x| as |x| → ∞) together with the star-shaped radial structure and the prescribed mean curvature equation imply that 1 − |∇u|^2 decays at a rate sufficient for the surface integral over large spheres to vanish as the radius tends to infinity (specifically, the relevant integrand is o(|x|^{-1}) in the measure induced by the graph). This is a consequence of the radial symmetry and the integrability of H. To make the argument fully transparent, we will add a short remark or auxiliary estimate in Section 5 deriving the necessary decay rate of |∇u| from the given assumptions. revision: partial

Circularity Check

0 steps flagged

No significant circularity; results are independent existence theorems

full rationale

The paper derives existence and uniqueness of entire spacelike radial graphs with prescribed mean curvature H via standard quasilinear elliptic estimates and integral identities under explicit decay and regularity assumptions on H that ensure the graph remains spacelike and asymptotic to the light cone. The Willmore-type inequality and L^p non-existence results follow directly from these a priori bounds and vanishing boundary terms without reduction to fitted inputs or self-citation chains. All load-bearing steps are self-contained against external PDE theory and do not invoke prior author work as a uniqueness theorem or ansatz.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The work rests on standard axioms of Lorentzian differential geometry and elliptic PDE theory for hypersurfaces; no free parameters or invented entities are indicated in the abstract.

axioms (1)
  • standard math The Lorentz-Minkowski space L^{m+1} is equipped with its standard flat metric of signature (m,1) and the mean curvature operator for spacelike hypersurfaces is well-defined and elliptic under the spacelike condition.
    Invoked throughout the setup of radial graphs and prescribed curvature problems.

pith-pipeline@v0.9.0 · 5383 in / 1313 out tokens · 32791 ms · 2026-05-08T06:57:17.857127+00:00 · methodology

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Reference graph

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