Fundamental and spectral properties of some classes of non-normal operators on a Hilbert space
| dc.contributor.author | FELLAG ARIOUAT, Ayyoub | |
| dc.date.accessioned | 2026-05-26T08:43:30Z | |
| dc.date.available | 2026-05-26T08:43:30Z | |
| dc.date.issued | 2026 | |
| dc.description | THESIS For obtaining the LMD doctorate degree Specialty: Operator Theory | en_US |
| dc.description.abstract | The purpose of this thesis is to investigate several properties of certain classes of nonnormal linear bounded operators acting on a separable complex Hilbert space specifically, those operators that fail to commute with their adjoints. We present a collection of essential structural and spectral characteristics that extend well-known properties of normal operators. These include 1. orthogonal decompositions, 2. restrictions concerning invariant subspaces, 3. Bishop’s property , 4. the single-valued extension property, 5. isoloid and polaroid operators In addition, new results are obtained regarding invariant subspaces and the behavior of the Riesz idempotent associated with these operator classes. The methods rely mainly on the theory of orthogonal decompositions, as well as on the study of invariant and reducing subspaces, which together form the theoretical framework of this research. | en_US |
| dc.identifier.uri | http://dspace.univ-chlef.dz/handle/123456789/2451 | |
| dc.publisher | Aissa NASLI BAKIR / Tayeb HADJ KADDOUR | en_US |
| dc.subject | Quasi-normal operator of order n | en_US |
| dc.subject | k-quasi-normal operator of order n | en_US |
| dc.subject | Weyl’s Theorem | en_US |
| dc.title | Fundamental and spectral properties of some classes of non-normal operators on a Hilbert space | en_US |
| dc.type | Thesis | en_US |