Completeness and modular cross-symmetry in normed linear spaces
نویسندگان
چکیده
منابع مشابه
On Linear Functional Equations and Completeness of Normed Spaces
The aim of this note is to give a type of characterization of Banach spaces in terms of the stability of functional equations. More precisely, we prove that a normed space X is complete if there exists a functional equation of the type n ∑ i=1 aif(φi(x1, . . . , xk)) = 0 (x1, . . . , xk ∈ D) with given real numbers a1, . . . , an, given mappings φ1 . . . , φn : D k → D and unknown function f : ...
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It is well known that every (real or complex) normed linear space $L$ is isometrically embeddable into $C(X)$ for some compact Hausdorff space $X$. Here $X$ is the closed unit ball of $L^*$ (the set of all continuous scalar-valued linear mappings on $L$) endowed with the weak$^*$ topology, which is compact by the Banach--Alaoglu theorem. We prove that the compact Hausdorff space $X$ can ...
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Let T be any normed linear space [l, p. S3]. Then an inner product is defined in T if to each pair of elements x and y there is associated a real number (x, y) in such a way that (#, y) » (y, x), \\x\\ = (#, #), (x, y+z) = (#,y) + (x, 2), and (/#,y) = /(#, y) for all real numbers /and elements x and y. An inner product can be defined in T if and only if any two-dimensional subspace is equivalen...
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ژورنال
عنوان ژورنال: Czechoslovak Mathematical Journal
سال: 1992
ISSN: 0011-4642,1572-9141
DOI: 10.21136/cmj.1992.128311