Global and blow-up solutions for a non-local integrable equation with applications to geometry
Nilay Duruk Mutlubas, Igor Leite Freire
TL;DR
The paper analyzes a non-local, Camassa-Holm–type evolution equation tied to pseudospherical geometry. It establishes global well-posedness in high-order Sobolev spaces under a nonnegative initial momentum and proves a sharp finite-time blow-up criterion when this sign condition fails, including an explicit blow-up time formula. An inductive hierarchy of energy functionals demonstrates the propagation of regularity across spatial derivatives, applicable to both periodic and non-periodic domains. The authors then connect these PDE results to geometry, showing that the solutions generate metrics of Gaussian curvature $-1$ on pseudospherical surfaces, with the metric degenerating at blow-up.
Abstract
We establish the global existence of higher-order Sobolev solutions for a non-local integrable evolution equation arising in the study of pseudospherical surfaces and non-linear wave propagation. Under a natural assumption on the initial momentum, we prove that the solution remains globally regular in arbitrary finite-order Sobolev spaces. The proof relies on an inductive energy method involving a hierarchy of functional estimates and applies to both the periodic and non-periodic settings. We determine a criterion for the existence of blow-up solutions. The consequences of these qualitative properties of the solutions on Riemannian surfaces determined by the solutions of the equation are investigated.
