RT Journal Article T1 Invariant subspaces for positive operators on Banach spaces with unconditional basis A1 Gallardo Gutiérrez, Eva Antonia A1 González Doña, Javier A1 Tradacete Pérez, Pedro AB We prove that every lattice homomorphism acting on a Banach space X with the lattice structure given by an unconditional basis has a non-trivial closed invariant subspace. In fact, it has a non-trivial closed invariant ideal, which is no longer true for every positive operator on such a space. Motivated by these examples, we characterize tridiagonal positive operators without non-trivial closed invariant ideals on X extending to this context a result of Grivaux on the existence of non-trivial closed invariant subspaces for tridiagonal operators. PB American Mathematical Society SN 0002-9939 YR 2022 FD 2022-06-16 LK https://hdl.handle.net/20.500.14352/71793 UL https://hdl.handle.net/20.500.14352/71793 LA eng NO Gallardo Gutiérrez, E. A., González Doña, J. & Tradecete Pérez, P. Invariant subspaces for positive operators on Banach spaces with unconditional basis. 16 de febrero de 2022. Proceedings of the American Mathematical Society, https://doi.org/10.1090/proc/16026. NO Ministerio de Ciencia, Innovación y Universidades (España)/Fondo Europeo de Desarrollo Regional NO Centro de Excelencia Severo Ochoa NO Universidad Complutense de Madrid DS Docta Complutense RD 27 abr 2025