Cobos Díaz, FernandoSegurado, Alba2023-06-202023-06-2020120039-322310.4064/sm213-3-4https://hdl.handle.net/20.500.14352/43900We study limiting K- and J-methods for arbitrary Banach couples. They are related by duality and they extend the methods already known in the ordered case. We investigate the behaviour of compact operators and we also discuss the representation of the methods by means of the corresponding dual functional. Finally, some examples of limiting function spaces are given.engjournal articlehttps//doi.org/10.4064/sm213-3-4http://journals.impan.gov.pl/sm/Inf/213-3-4.htmlrestricted access517.518.85517.538.7519.652J-functionalK-functionalLimiting real interpolationCompact operatorsLorentz-Zygmund function spacesAnálisis matemático1202 Análisis y Análisis Funcional