Analysis
16 results · 29 papers · 11 with a Lean formalization
Proves large-data global existence and uniqueness for the three-dimensional, one-species relativistic Vlasov–Maxwell system. Smooth admissible initial data may be arbitrary provided the particle density is compactly supported and the electromagnetic fields have finite energy and bounded derivatives of every order; the solution remains smooth on every finite time interval.
1 paperLeanreasoningConstructs two distinct global entropy solutions of the three-dimensional periodic hard-sphere Boltzmann equation from the same nonnegative initial density, with bounded velocity support and finite mass, energy and absolute entropy. Both are strongly continuous in L1 and satisfy exact local conservation of mass, momentum and kinetic energy.
2 papersLeanDerives the nonlinear Boltzmann equation from three-dimensional grand-canonical Newtonian gases throughout every regular kinetic interval with uniform Gaussian decay. Stable finite-range radial potentials may have attractive wells and a singular repulsive core; initial pair exclusion and spatially summable Gaussian density and gradient bounds are assumed. A companion gives finite-dimensional hard-sphere Gaussian fluctuations, centered at the exact microscopic expectation and governed by the linear fluctuating Boltzmann equation.
2 papersZero-frequency measurements on any nonempty open boundary patch determine a smooth metric and smooth unitary connection on a trivial Hermitian rank-two bundle over a compact connected manifold of dimension at least three, up to diffeomorphism and gauge fixed on that patch. Inputs and observations use the same patch. In contrast, distinct uniformly positive bounded measurable scalar conductivities on a three-dimensional ball can have identical full-boundary data.
3 papersLeanResolves the interior regularity conjecture for reduced absolute planar Mumford–Shah minimizers with bounded fidelity data. Locally, the closed discontinuity set is a \(C^{1,\alpha}\) arc, a regular crack tip, or three arcs meeting at \(120^\circ\); only finitely many global connected components meet any compact interior region.
1 paperEstablishes seven as the first dimension admitting a nonflat, one-homogeneous global minimizer of the one-phase Bernoulli energy. Consequently, minimizing free boundaries are smooth through dimension six, and their singular sets have dimension at most \(n-7\) in higher dimensions.
1 paperLeanResolves the three-dimensional Ball–Evans approximation problem: every \(W^{1,p}\) homeomorphism between arbitrary bounded domains in ℝ3, for \(1\le p\lt \infty\), is a strong \(W^{1,p}\) limit of smooth diffeomorphisms onto the same target.
2 papersProves a strict form of Burdzy's simply connected hot spots conjecture. On every smooth bounded simply connected planar domain, each nonzero eigenfunction for the first positive Neumann eigenvalue has no interior critical point, so all global extrema lie on the boundary. Eigenvalue multiplicity is allowed.
1 paperLeanResolves the subcritical Lane–Emden conjecture and its weighted Hénon extension. For n ≥ 2, \(p,q\gt 0\) and real A, B, the system \(-\Delta u=|x|^A v^p\), \(-\Delta v=|x|^B u^q\) has no positive entire solution when \((n+A)/(p+1)+(n+B)/(q+1)\gt n-2\), with solutions continuous at the origin and classical elsewhere. No symmetry or growth assumption is needed. Known radial existence gives the exact existence criterion for n ≥ 3 and \(A,B\gt -2\).
1 paperLeanFor a sufficiently large odd nonlinearity power, constructs a nonempty open set of initial data in \(H^k(\mathbb T^{12})\), with k > 8, whose solutions of the scalar defocusing nonlinear Schrödinger equation blow up in finite time. Thus finite-time blowup is stable under Sobolev perturbations in this supercritical regime.
1 paperLeanProves that full static boundary displacement-to-traction data determine both smooth real Lamé moduli on every bounded connected smooth domain in ℝ3, provided μ > 0 and \(3\lambda+2\mu\gt 0\) on the closure. Neither analyticity, proximity to constant coefficients nor prior knowledge near the boundary is required.
1 paperLeanAn optimal three-particle Coulomb configuration need not be a deterministic function of the first particle, even for smooth identical spatial densities. The Monge and Kantorovich infima agree, but the Monge infimum is not attained. The same phenomenon occurs for every inverse-power Riesz exponent in each dimension at least two, with a suitable density in each case.
1 paperLeanFor uniform source measure ρ on a compact convex body with interior in dimension at least two, quadratic optimal transport maps satisfy \(\|T_\mu-T_\nu\|_{L^2(\rho)}\le C W_2(\mu,\nu)^{1/3}\) uniformly over targets in a fixed compact set. The exponent is sharp, even for three-atom targets, disproving Letrouit's conjectured square-root bound.
1 paperLeanProves De Giorgi's conjecture at its sharp dimension-eight endpoint: every entire C2 solution \(u:\mathbb R^8\to(-1,1)\) of \(\Delta u=u^3-u\) that is strictly increasing in one direction depends on only one linear coordinate. A stronger theorem classifies all stable entire solutions \(v:\mathbb R^7\to[-1,1]\) as constant wells or planar transitions, without an energy-growth assumption.
1 paperConstructs viscous incompressible flows starting from rest on a fixed flat three-dimensional domain that perform universal computation under smooth external forcing. A terminating compiler turns a Turing machine and input into a finite program for the force, so a designated particle reaches a fixed region exactly when the machine halts. The viscosity is fixed, positive and computable.
9 papersLeanProves uniform interior \(C^{1,\alpha_d}\) regularity for bounded infinity-harmonic functions in every dimension d ≥ 3, for a positive exponent depending only on dimension. The gradient's supremum norm and Hölder seminorm on the half unit ball are bounded by a dimension-dependent constant times the oscillation on the unit ball. The exponent is not explicit.
1 paperNo result matches this filter yet.