2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/79898We introduce a new class of nonlinear equations admitting a representation in terms of Darboux-covariant compatibility conditions. Their special cases are, in particular, (i) the "general" von Neumann equation $i\dotρ=[H,f(ρ)]$, with $[f(ρ),ρ]=0$, (ii) its generalization involving certain functions $f(ρ)$ which are non-Abelian in the sense that $[f(ρ),ρ]\neq0$, and (iii) the Nahm equations.LaTeX, 19 pagesExactly Solvable and Integrable SystemsHigh Energy Physics - TheoryQuantum Physicstext