2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/94405We study the integrable systems in higher dimensions which can be written not by the Hirota's bilinear form but by the trilinear form. We explicitly discuss about the Bogoyavlenskii-Schiff(BS) equation in (2 + 1) dimensions. Its analytical proof of multi soliton solution and a new feature are given. Being guided by the strong symmetry, we also propose a new equation in (3 + 1) dimensions.14 pages, 8 figures(fpc30017@bkc.ritsumei.ac.jp), uses ioplppt.styExactly Solvable and Integrable Systemstext