2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/91638We demonstrate that multiple copies of a bipartite entangled pure state may serve as a catalyst for certain entanglement transformations while a single copy cannot. Such a state is termed a "multiple-copy catalyst" for the transformations. A trade-off between the number of copies of source state and that of the catalyst is also observed. These results can be generalized to probabilistic entanglement transformations directly.Essentially the journal version. 7 pages, no figures. Minor correctionsQuantum Physicstext