The local well-posedness, blow-up phenomena and ill-posedness of a new fifth-order Camassa-Holm type equation
Yiyao Lian, Zhaoyang Yin
TL;DR
This work analyzes a new fifth-order Camassa–Holm type equation with cubic nonlinearities and higher-order dispersion. It develops local well-posedness in Besov spaces via a transport-based construction and Moser-type estimates, establishes a sharp blow-up criterion, and derives a precise blow-up time using conservation laws and a Lagrangian framework. It further demonstrates ill-posedness at the critical level $H^{\frac{1}{2}}$ through norm inflation, highlighting instability of the dynamics at minimal regularity. Together, these results extend the CH family to higher-order dispersion, providing rigorous conditions for global behavior, finite-time blow-up, and ill-posedness at critical regularity.
Abstract
In this paper, we study a new fifth-order Camassa-Holm type equation derived by Li \cite{Li.Z}. We firstly establish the local well-posedness in the sense of Hadamard for the Cauchy problem of the new fifth-order Camassa-Holm type equation in Besov spaces. Secondly, we obtain blow-up criteria. Building upon this, by utilizing the conservation laws and establishing local boundedness, we derive a blow-up result that precisely determines the blow-up time. Finally, the ill-posedness of the new fifth-order Camassa-Holm type equation in the critical Sobolev space $H^{\frac{1}{2}}$ is established via a norm inflation argument.
