Invariant subspace problem and compact operators on non-Archimedean Banach spaces

• Main Authors: M. Babahmed, Azzedine El asri
• Format: Article
• Language: English
• Published: University of Extremadura 2020-12-01
• Series: Extracta Mathematicae
• Subjects: Invariant subspace; hyperinvariant subspace; compact operator; t-orthogonal basis; quasi null vector; triangular operator
• Online Access: https://publicaciones.unex.es/index.php/EM/article/view/363
• ISSN: 0213-8743; 2605-5686

In this paper, the invariant Subspace Problem is studied for the class of non-Archimedean compact operators on an infinite-dimensional Banach space E over a nontrivial complete non-Archimedean valued field K. Our first main result (Theorem 9) asserts that if K is locally compact, then each compact operator on E possessing a quasi null vector admits a nontrivial hyperinvariant closed subspace. In the second one (Theorem 17), we prove that each bounded operator on E which contains a cyclic quasi null vector can be written as the sum of a triangular operator and a compact shift operator, each one of them possesses a nontrivial invariant closed subspace. Finally, we conclude that if K is algebraically closed, then every compact operator on E either has a nontrivial invariant closed subspace or is a sum of upper triangular operator and shift operator, each of them is compact and has a nontrivial invariant closed subspace.