“…The scalar CH equation, which corresponds to the case where ρ(t, x) = ρ 0 (x) = 0, was introduced by Camassa and Holm in the fundamental paper [7], and its analysis has been pervasive. Other generalizations of the Camassa-Holm equation exist; see, for example, [8,9,13,21,33]. The 2CH system experiences wave breaking in the sense that the spatial derivative of u becomes unbounded while keeping its H 1 (R) norm finite.…”