Extensions of linear operators from hyperplanes of $l^{(n)}_\infty$
Baronti, Marco ; Fragnelli, Vito ; Lewicki, Grzegorz
Commentationes Mathematicae Universitatis Carolinae, Tome 36 (1995), p. 443-458 / Harvested from Czech Digital Mathematics Library
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Let $Y \subset l^{(n)}_{\infty }$ be a hyperplane and let $A \in {\Cal L}(Y)$ be given. Denote $$ \align {\Cal A} = & \{L\in {\Cal L}(l^{(n)}_{\infty },Y):L\mid Y = A\} \text{ and} \ & \lambda_{A} = \inf \{\parallel L \parallel : L\in {\Cal A}\}. \endalign $$ In this paper the problem of calculating of the constant $\lambda_{A}$ is studied. We present a complete characterization of those $A \in {\Cal L}(Y)$ for which $\lambda_{A} = \parallel A \parallel $. Next we consider the case $\lambda_{A} > \parallel A \parallel $. Finally some computer examples will be presented.

Publié le : 1995-01-01
Classification:  41A35,  41A52,  41A55,  41A65,  46A22,  47A20 
@article{118772,
     author = {Marco Baronti and Vito Fragnelli and Grzegorz Lewicki},
     title = {Extensions of linear operators from hyperplanes of $l^{(n)}\_\infty$},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     volume = {36},
     year = {1995},
     pages = {443-458},
     zbl = {0831.41014},
     mrnumber = {1364484},
     language = {en},
     url = {http://dml.mathdoc.fr/item/118772}
}

Baronti, Marco; Fragnelli, Vito; Lewicki, Grzegorz. Extensions of linear operators from hyperplanes of $l^{(n)}_\infty$. Commentationes Mathematicae Universitatis Carolinae, Tome 36 (1995) pp. 443-458. http://gdmltest.u-ga.fr/item/118772/

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