On functions with the Cauchy difference bounded by a functional. Part II

We are going to consider the functional inequality f(x+y)−f(x)−f(y)≥ϕ(x,y), x,y∈X, where (X,+) is an abelian group, and ϕ:X×X→ℝ and f:X→ℝ are unknown mappings. In particular, we will give conditions which force biadditivity and symmetry of ϕ and the representation f(x)=(1/2)ϕ(x,x)+a(x) for x∈X, wher...

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Main Author: Włodzimierz Fechner
Format: Article
Language:English
Published: Wiley 2005-01-01
Series:International Journal of Mathematics and Mathematical Sciences
Online Access:http://dx.doi.org/10.1155/IJMMS.2005.1889
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author Włodzimierz Fechner
author_facet Włodzimierz Fechner
author_sort Włodzimierz Fechner
collection DOAJ
description We are going to consider the functional inequality f(x+y)−f(x)−f(y)≥ϕ(x,y), x,y∈X, where (X,+) is an abelian group, and ϕ:X×X→ℝ and f:X→ℝ are unknown mappings. In particular, we will give conditions which force biadditivity and symmetry of ϕ and the representation f(x)=(1/2)ϕ(x,x)+a(x) for x∈X, where a is an additive function. In the present paper, we continue and develop our earlier studies published by the author (2004).
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1687-0425
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series International Journal of Mathematics and Mathematical Sciences
spelling doaj-art-2eac7bf5c8804734826e6cec6d6ee1892025-02-03T01:07:47ZengWileyInternational Journal of Mathematics and Mathematical Sciences0161-17121687-04252005-01-012005121889189810.1155/IJMMS.2005.1889On functions with the Cauchy difference bounded by a functional. Part IIWłodzimierz Fechner0Institute of Mathematics, Faculty of Mathematics, Physics and Chemistry, University of Silesia, 14 Bankowa Street, Katowice 40-007, PolandWe are going to consider the functional inequality f(x+y)−f(x)−f(y)≥ϕ(x,y), x,y∈X, where (X,+) is an abelian group, and ϕ:X×X→ℝ and f:X→ℝ are unknown mappings. In particular, we will give conditions which force biadditivity and symmetry of ϕ and the representation f(x)=(1/2)ϕ(x,x)+a(x) for x∈X, where a is an additive function. In the present paper, we continue and develop our earlier studies published by the author (2004).http://dx.doi.org/10.1155/IJMMS.2005.1889
spellingShingle Włodzimierz Fechner
On functions with the Cauchy difference bounded by a functional. Part II
International Journal of Mathematics and Mathematical Sciences
title On functions with the Cauchy difference bounded by a functional. Part II
title_full On functions with the Cauchy difference bounded by a functional. Part II
title_fullStr On functions with the Cauchy difference bounded by a functional. Part II
title_full_unstemmed On functions with the Cauchy difference bounded by a functional. Part II
title_short On functions with the Cauchy difference bounded by a functional. Part II
title_sort on functions with the cauchy difference bounded by a functional part ii
url http://dx.doi.org/10.1155/IJMMS.2005.1889
work_keys_str_mv AT włodzimierzfechner onfunctionswiththecauchydifferenceboundedbyafunctionalpartii