Orthogonalities and functional equations

Verfasser / Beitragende:
[Justyna Sikorska]
Ort, Verlag, Jahr:
2015
Enthalten in:
Aequationes mathematicae, 89/2(2015-04-01), 215-277
Format:
Artikel (online)
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024 7 0 |a 10.1007/s00010-014-0288-0  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s00010-014-0288-0 
100 1 |a Sikorska  |D Justyna  |u Institute of Mathematics, University of Silesia, Bankowa 14, 40-007, Katowice, Poland  |4 aut 
245 1 0 |a Orthogonalities and functional equations  |h [Elektronische Daten]  |c [Justyna Sikorska] 
520 3 |a In this survey we show how various notions of orthogonality appear in the theory of functional equations. After introducing some orthogonality relations, we give examples of functional equations postulated for orthogonal vectors only. We show their solutions as well as some applications. Then we discuss the problem of stability of some of them considering various aspects of the problem. In the sequel, we mention the orthogonality equation and the problem of preserving orthogonality. Last, but not least, in addition to presenting results, we state some open problems concerning these topics. Taking into account the big amount of results concerning functional equations postulated for orthogonal vectors which have appeared in the literature during the last decades, we restrict ourselves to the most classical equations. 
540 |a The Author(s), 2014 
690 7 |a Orthogonality  |2 nationallicence 
690 7 |a Birkhoff orthogonality  |2 nationallicence 
690 7 |a James isosceles orthogonality  |2 nationallicence 
690 7 |a approximate orthogonality  |2 nationallicence 
690 7 |a inner product space  |2 nationallicence 
690 7 |a normed space  |2 nationallicence 
690 7 |a Hilbert modules  |2 nationallicence 
690 7 |a norm derivative  |2 nationallicence 
690 7 |a semi-inner product  |2 nationallicence 
690 7 |a Cauchy equation  |2 nationallicence 
690 7 |a quadratic equation  |2 nationallicence 
690 7 |a exponential equation  |2 nationallicence 
690 7 |a orthogonal additivity  |2 nationallicence 
690 7 |a stability  |2 nationallicence 
690 7 |a orthogonality equation  |2 nationallicence 
690 7 |a orthogonality preserving property  |2 nationallicence 
690 7 |a linear preservers  |2 nationallicence 
690 7 |a isometry  |2 nationallicence 
690 7 |a approximate isometry  |2 nationallicence 
773 0 |t Aequationes mathematicae  |d Springer Basel  |g 89/2(2015-04-01), 215-277  |x 0001-9054  |q 89:2<215  |1 2015  |2 89  |o 10 
856 4 0 |u https://doi.org/10.1007/s00010-014-0288-0  |q text/html  |z Onlinezugriff via DOI 
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900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
949 |B NATIONALLICENCE  |F NATIONALLICENCE  |b NL-springer 
950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s00010-014-0288-0  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 100  |E 1-  |a Sikorska  |D Justyna  |u Institute of Mathematics, University of Silesia, Bankowa 14, 40-007, Katowice, Poland  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Aequationes mathematicae  |d Springer Basel  |g 89/2(2015-04-01), 215-277  |x 0001-9054  |q 89:2<215  |1 2015  |2 89  |o 10