Global semigroup of conservative weak solutions of the two-component Novikov equation
Kenneth H. Karlsen, Yan Rybalko
TL;DR
This work addresses the global evolution of the two-component Novikov equation, where wave breaking and energy concentration pose major challenges. By transforming the problem along characteristics into a semilinear, nonlocal ODE system for variables $(U,V,W,Z,q)$ and introducing a Radon energy measure $\mu_{(t)}$, the authors construct a global conservative weak solution in the energy space $\Sigma$ and establish a corresponding data-to-solution continuity in the uniform norm. They prove global well-posedness of the ODE system, reconstruct the physical fields $(u,v)$ from the transformed variables, and define measure-valued energy transport equations that describe energy concentration during wave breaking. These ingredients are assembled into a global semigroup $\Psi_t$ acting on an augmented data space $\mathcal{D}$, yielding unique continuation of solutions past collisions and preserving key invariants such as $E_{u_0}, E_{v_0}, G_0, H_0$. The results provide a rigorous, energy-centered framework for the global dynamics of this nonlocal, two-component system with potential two-way peakon interactions and energy concentration phenomena.
Abstract
We study the Cauchy problem for the two-component Novikov system with initial data $u_0, v_0$ in $H^1(\mathbb{R})$ such that the product $(\partial_x u_0)\partial_x v_0$ belongs to $L^2(\mathbb{R})$. We construct a global semigroup of conservative weak solutions. We also discuss the potential concentration phenomena of $(\partial_x u)^2dx$, $(\partial_x v)^2dx$, and $\left((\partial_x u)^2(\partial_x v)^2\right)dx$, which contribute to wave-breaking and may occur for a set of time with nonzero measure. Finally, we establish the continuity of the data-to-solution map in the uniform norm.
