Non-uniqueness of Hölder continuous solutions for stochastic Euler and Hypodissipative Navier-Stokes equations

Abstract: Here we construct infinitely many H\"older continuous global-in-time and stationary solutions to the stochastic Euler and hypodissipative Navier-Stokes equations in the space $C(\mathbb{R};C^{\vartheta})$ for $0<\vartheta<\frac{5}{7}\beta$, with $0<\beta< \frac{1}{24}$ and $0<\beta<\min\left{\frac{1-2\alpha}{3},\frac{1}{24}\right}$ respectively. A modified stochastic convex integration scheme, using Beltrami flows as building blocks and propagating inductive estimates both pathwise and in expectation, plays a pivotal role to improve the regularity of H\"older continuous solutions for the underlying equations. As a main novelty with respect to the related literature, our result produces solutions with noteworthy H\"older exponents.