lt;<.$ A real-valued function g on X is called isotone with respect to lt;<$ if g(x) $\le$ g(y) whenever x, y $\in$ X and X lt;<$ y. Let G(X) be the set of all isotone functions on x. The problem being considered here is:(UNFORMATTED TABLE O…" /> Dual algorithm for L1 isotonic optimization on a partially ordered set