English

Many-point tropical relaxation and the Monge--Ampère equation

Analysis of PDEs 2026-07-28 v1 Algebraic Geometry Metric Geometry

Abstract

We construct an incidence-driven tropical approximation of the planar Aleksandrov Monge--Amp\`ere equation. Let ΩR2\Omega\subset\mathbb R^2 be a bounded open convex domain, let KΩK\Subset\Omega, and let FN=GPN0ΩF_N=G_{P_N}0_\Omega be the minimal nonnegative concave tropical series with integral slopes, zero boundary values, and corner locus containing an NN-point set PNKP_N\subset K. For universally generic configurations whose empirical measures converge to μ\mu, N1/2FNFμ,ΩN^{-1/2}F_N\longrightarrow F_{\mu,\Omega} uniformly on Ω\overline\Omega, where Fμ,ΩF_{\mu,\Omega} is the unique continuous concave Aleksandrov solution of MA(F)=μ\mathrm{MA}(F)=\mu with zero boundary values. On every compact LΩL\Subset\Omega we prove an O(N1/2)O(N^{-1/2}) bounded-Lipschitz-type estimate for the curvature discrepancy. No regularity or strict-convexity assumption is imposed on Ω\partial\Omega. For rational polygons, strong genericity holds on an open dense full-measure locus. The tropical curve has exactly NN bounded cells, the marked dual edges form a spanning tree, and every compact internal edge has weight one. These finite statements yield global weak curvature convergence and the exact identity MA(FN)(Ω)=N1+12Dterm(FN)\mathrm{MA}(F_N)(\Omega^\circ)=N-1+\frac{1}{2}D_{\mathrm{term}}(F_N), with Dterm(FN)=O(N)D_{\mathrm{term}}(F_N)=O(\sqrt N). The proof combines tropical interpolation, semilinear marked topology, an Euler--Pick curvature formula, minimal coefficient deformations, tangential coarea, and a weighted Crofton estimate uniform over rational polygonal exhaustions. We also obtain almost-sure limits for random point clouds, full affine covariance of the continuum solution, and a configuration-dependent Abelian-sandpile diagonal.

Keywords

Cite

@article{arxiv.2607.25878,
  title  = {Many-point tropical relaxation and the Monge--Ampère equation},
  author = {Nikita Kalinin and Ernesto Lupercio and Higinio Serrano and Mikhail Shkolnikov},
  journal= {arXiv preprint arXiv:2607.25878},
  year   = {2026}
}

Comments

62 pages, 3 figures