Geodesic
On the defect spectrum of an extension of a Banach space operator
Czechoslovak Mathematical Journal, Tome 48 (1998) no. 4, pp. 609-616 Cet article a éte moissonné depuis la source Czech Digital Mathematics Library

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Let $T$ be an operator acting on a Banach space $X$. We show that between extensions of $T$ to some Banach space $Y\supset X$ which do not increase the defect spectrum (or the spectrum) it is possible to find an extension with the minimal possible defect spectrum.
Let $T$ be an operator acting on a Banach space $X$. We show that between extensions of $T$ to some Banach space $Y\supset X$ which do not increase the defect spectrum (or the spectrum) it is possible to find an extension with the minimal possible defect spectrum.
Classification : 47A10, 47A20 
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     title = {On the defect spectrum of an extension of a {Banach} space operator},
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}
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Kordula, Vladimír. On the defect spectrum of an extension of a Banach space operator. Czechoslovak Mathematical Journal, Tome 48 (1998) no. 4, pp. 609-616. http://geodesic.mathdoc.fr/item/CMJ_1998_48_4_a0/

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