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arXiv · 2507.13535

The Cauchy problem for the integrable RZQ equation

John Holmes·Katie Massey·Ryan C. Thompson
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Abstract

In this paper we study a new integrable fifth-order Camassa-Holm (CH)-type equation derived by Reyes, Zhu, and Qiao, which we call the RZQ equation. The m-form of this equation possesses a striking similarity to the m-form of the CH equation. However, unlike the CH equation, the nonlocal form of this equation cannot be interpreted as a nonlocal perturbation of Burgers' equation. We prove that the initial value problem corresponding to the RZQ equation is well-posed in the sense of Hadamard, in Sobolev spaces $H^s$, $s>7/2$. We further show that the data-to-solution map is not uniformly continuous in the $H^s$ topology, though it is H\"older continuous in a weaker topology. The initial value problem corresponding to the RZQ equation is ill-posed in $H^s$ for $s<7/2$.

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John Holmes, Katie Massey, Ryan C. Thompson. 2025-07-17. The Cauchy problem for the integrable RZQ equation. https://arxiv.org/abs/2507.13535

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