Kernel Methods for Some Transport Equations with Application to Learning Kernels for the Approximation of Koopman Eigenfunctions: A Unified Approach via Variational Methods, Green's Functions and the Method of Characteristics

This paper presents a unified framework that proves the equivalence of variational, Green's function, and characteristic-based methods for constructing reproducing kernels, enabling a data-driven, mesh-free approach to learning kernels that accurately approximate Koopman eigenfunctions and solve various linear transport equations.

Boumediene Hamzi, Houman Owhadi, Umesh Vaidya2026-03-10🔢 math

Scattering rigidity for Hamiltonian systems with an application to Finsler geometry

This paper establishes the scattering rigidity of positively homogeneous Hamiltonian systems on manifolds with boundary by proving that the Hamiltonian is uniquely determined up to boundary-fixing canonical transformations via the inversion of X-ray and light ray transforms on Hamiltonian curves, a result applied to demonstrate semiglobal lens rigidity for non-trapping Finsler manifolds.

Nikolas Eptaminitakis, Plamen Stefanov2026-03-10🔢 math

Quantifier elimination for lovely pairs of strongly geometric fields

This paper establishes that the theory of lovely pairs of any complete strongly geometric field theory with quantifier elimination admits quantifier elimination when expanded with predicates for linear independence and corresponding coordinate functions, thereby generalizing Delon's results to include dense pairs of real closed and pp-adically closed fields.

Pablo Cubides Kovacsics, Felipe Estrada, Juan Pérez, David Rincón2026-03-10🔢 math

A Note on the Gradient-Evaluation Sequence in Accelerated Gradient Methods

This paper resolves an open question in convex optimization by proving that the gradient-evaluation sequence in Nesterov's accelerated gradient descent method, including in projection-based and non-Euclidean settings, achieves the optimal O(L/k2)O(L/k^2) convergence rate for the objective function value, matching the performance of the standard solution sequence.

Yan Wu, Yipeng Zhang, Lu Liu, Yuyuan Ouyang2026-03-10🔢 math