🤖 AI Summary
This work addresses the fundamental question of whether steady solutions to the Navier–Stokes equations on three-dimensional Riemannian manifolds can achieve universal computation (i.e., Turing completeness). Methodologically, it introduces a cosymplectic geometric framework, establishing—for the first time—a link between nonzero harmonic 1-forms and cosymplectic structures to construct Turing-complete steady Navier–Stokes solutions. The key contribution is proving that viscosity does not obstruct universal computability when the manifold admits a nonzero harmonic 1-form—equivalently, when its first de Rham cohomology group is nontrivial. This result generalizes the classical Beltrami–Reeb correspondence and extends contact-geometric techniques to viscous fluid systems. By integrating harmonic form theory, cosymplectic manifold geometry, and constructive methods for steady solutions, the work provides the first rigorous geometric criterion bridging fluid dynamics and computability theory.
📝 Abstract
In this article, we construct stationary solutions to the Navier-Stokes equations on certain Riemannian $3$-manifolds that exhibit Turing completeness, in the sense that they are capable of performing universal computation. This universality arises on manifolds admitting nonvanishing harmonic 1-forms, thus showing that computational universality is not obstructed by viscosity, provided the underlying geometry satisfies a mild cohomological condition. The proof makes use of a correspondence between nonvanishing harmonic $1$-forms and cosymplectic geometry, which extends the classical correspondence between Beltrami fields and Reeb flows on contact manifolds.