2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/102445This paper is an expanded and more detailed version of our recent work in which the Operator Quantum Error Correction formalism was introduced. This is a new scheme for the error correction of quantum operations that incorporates the known techniques - i.e. the standard error correction model, the method of decoherence-free subspaces, and the noiseless subsystem method - as special cases, and relies on a generalized mathematical framework for noiseless subsystems that applies to arbitrary quantum operations. We also discuss a number of examples and introduce the notion of ``unitarily noiseless subsystems''.21 pages, to appear in Quantum Information & ComputationQuantum PhysicsFunctional AnalysisOperator AlgebrasOperator quantum error correctiontext