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Quadratic and quasi-quadratic functionals


Author: Peter Šemrl
Journal: Proc. Amer. Math. Soc. 119 (1993), 1105-1113
MSC: Primary 15A63; Secondary 16W10, 39B22
DOI: https://doi.org/10.1090/S0002-9939-1993-1158008-3
MathSciNet review: 1158008
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Abstract: In this note we show how Jordan $ {\ast}$-derivations arise as a "measure" of the representability of quasi-quadratic functionals by sesquilinear ones. Our main result can be considered as an extension of the Jordan-von Neumann characterization of pre-Hilbert space.


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DOI: https://doi.org/10.1090/S0002-9939-1993-1158008-3
Article copyright: © Copyright 1993 American Mathematical Society

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