Abstract
We show that if T is a narrow operator (for the definition see below) on X = X1 ⊕1 X2 or X = X1 ⊕∞ X2 then the restrictions to X 1 and X 2 are narrow and conversely. We also characterise by a version of the Daugavet property for positive operators on Banach lattices which unconditional sums of Banach spaces inherit the Daugavet property and we study the Daugavet property for ultraproducts.
Original language | English (US) |
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Pages (from-to) | 45-62 |
Number of pages | 18 |
Journal | Positivity |
Volume | 9 |
Issue number | 1 |
DOIs | |
State | Published - Mar 2005 |
Externally published | Yes |
Bibliographical note
Funding Information:The work of V.K. was supported by a grant from the Alexander-von-Humboldt Stiftung.
Keywords
- Daugavet property
- Narrow operator
- Strong Daugavet operator
- Ultraproducts of Banach spaces