2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/150943In this paper we solve positively the problem of (local) density of solutions of the (2+1)-dimentional integrable system describing triply orthogonal curvilinear coordinates in R^3 (a (2+1)-dimensional generalization of the 3-wave system) obtainable from a given initial solution with consecutive Bäcklund transformations (called Ribaucour transformations in classical differential geometry) in the space of all solutions of the system in question.7 pages (26 Kbytes), standard LaTeX 2.09, run twice to get the right cross-references. Resubmitted with the only correction: acknowledgment of grant RBFR 96-01-00050 supportExactly Solvable and Integrable Systemstext