2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/88794We present an improved protocol for entanglement purification of bipartite mixed states using several states at a time rather than two at a time as in the traditional recurrence method. We also present a generalization of the hashing method to n-partite cat states, which achieves a finite yield of pure cat states for any desired fidelity. Our results are compared to previous protocols.10 pages AMS-TeX with eps figures, to be published in the AMS Contemporary Math Series volume entitled "Quantum Computation & Quantum Information Science."Quantum Physicstext