doi:10.1007/s11117-024-01093-wengAnsorena, José L.Bello, GlenierUnconditional basic sequences in function spaces with applications to Orlicz spacesART-2024-140747We find conditions on a function space that ensure that it behaves as an -space in the sense that any unconditional basis of a complemented subspace of either is equivalent to the unit vector system of or has a subbasis equivalent to a disjointly supported basic sequence. This dichotomy allows us to classify the symmetric basic sequences of . Several applications to Orlicz function spaces are provided.2024http://zaguan.unizar.es/record/14691310.1007/s11117-024-01093-whttp://zaguan.unizar.es/record/146913oai:zaguan.unizar.es:146913info:eu-repo/grantAgreement/ES/DGA/E48-23Rinfo:eu-repo/grantAgreement/ES/MICINN/PID2022-137294NB-I00POSITIVITY 29, 1 (2024), 1-36byhttps://creativecommons.org/licenses/by/4.0/deed.esinfo:eu-repo/semantics/openAccess