“…Indeed, the local and global existence of solutions to the Cauchy problem for the MTM system (1.1) in the L 2 -based Sobolev spaces H m (R), m ∈ N can be proven with the standard contraction and energy methods, see review of literature in [26]. Low regularity solutions in L 2 (R) were already obtained for the MTM system by Selberg and Tesfahun [31], Candy [5], Huh [13,14,15], and Zhang [35,36]. The well-posedness results can be formulated as follows.…”