Stability and hyperstability of a quadratic functional equation and a characterization of inner product spaces
We have proved theHyers-Ulam stability and the hyperstability of the quadratic functional equation f (x + y + z) + f (x + y − z) + f (x − y + z) + f (−x + y + z) = 4[f (x) + f (y) + f (z)] in the class of functions from an abelian group G into a Banach space.
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De Gruyter
2018-11-01
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| Series: | Demonstratio Mathematica |
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| Online Access: | http://www.degruyter.com/view/j/dema.2018.51.issue-1/dema-2018-0027/dema-2018-0027.xml?format=INT |
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doaj-45d5ddc42d454eb4bd8a878dd80fe6652020-11-24T23:55:37ZengDe GruyterDemonstratio Mathematica2391-46612018-11-0151129530310.1515/dema-2018-0027dema-2018-0027Stability and hyperstability of a quadratic functional equation and a characterization of inner product spacesKim Gwang Hui0El-Fassi Iz-iddine1Park Choonkil2Department of Mathematics, Kangnam University, Yongin,Gyoenggi, Republic of KoreaDepartment of Mathematics, Faculty of Sciences, University of Ibn Tofail,Kenitra, MoroccoResearch Institute for Natural Sciences, Hanyang University,Seoul, Republic of KoreaWe have proved theHyers-Ulam stability and the hyperstability of the quadratic functional equation f (x + y + z) + f (x + y − z) + f (x − y + z) + f (−x + y + z) = 4[f (x) + f (y) + f (z)] in the class of functions from an abelian group G into a Banach space.http://www.degruyter.com/view/j/dema.2018.51.issue-1/dema-2018-0027/dema-2018-0027.xml?format=INTHyers-Ulam stabilityhyperstabilityquadratic functional equationfixed point theorem39B8239B5247H1447H10 |
| collection |
DOAJ |
| language |
English |
| format |
Article |
| sources |
DOAJ |
| author |
Kim Gwang Hui El-Fassi Iz-iddine Park Choonkil |
| spellingShingle |
Kim Gwang Hui El-Fassi Iz-iddine Park Choonkil Stability and hyperstability of a quadratic functional equation and a characterization of inner product spaces Demonstratio Mathematica Hyers-Ulam stability hyperstability quadratic functional equation fixed point theorem 39B82 39B52 47H14 47H10 |
| author_facet |
Kim Gwang Hui El-Fassi Iz-iddine Park Choonkil |
| author_sort |
Kim Gwang Hui |
| title |
Stability and hyperstability of a quadratic functional equation and a characterization of inner product spaces |
| title_short |
Stability and hyperstability of a quadratic functional equation and a characterization of inner product spaces |
| title_full |
Stability and hyperstability of a quadratic functional equation and a characterization of inner product spaces |
| title_fullStr |
Stability and hyperstability of a quadratic functional equation and a characterization of inner product spaces |
| title_full_unstemmed |
Stability and hyperstability of a quadratic functional equation and a characterization of inner product spaces |
| title_sort |
stability and hyperstability of a quadratic functional equation and a characterization of inner product spaces |
| publisher |
De Gruyter |
| series |
Demonstratio Mathematica |
| issn |
2391-4661 |
| publishDate |
2018-11-01 |
| description |
We have proved theHyers-Ulam stability and the hyperstability of the quadratic functional equation f (x + y + z) + f (x + y − z) + f (x − y + z) + f (−x + y + z) = 4[f (x) + f (y) + f (z)] in the class of functions from an abelian group G into a Banach space. |
| topic |
Hyers-Ulam stability hyperstability quadratic functional equation fixed point theorem 39B82 39B52 47H14 47H10 |
| url |
http://www.degruyter.com/view/j/dema.2018.51.issue-1/dema-2018-0027/dema-2018-0027.xml?format=INT |
| work_keys_str_mv |
AT kimgwanghui stabilityandhyperstabilityofaquadraticfunctionalequationandacharacterizationofinnerproductspaces AT elfassiiziddine stabilityandhyperstabilityofaquadraticfunctionalequationandacharacterizationofinnerproductspaces AT parkchoonkil stabilityandhyperstabilityofaquadraticfunctionalequationandacharacterizationofinnerproductspaces |
| _version_ |
1725461504348651520 |