
doi: 10.1515/jaa.2007.19
Suppose that \(M\) is a Abelian group in which the unique division by 2 and 3 is performable and \(S\) is an abstract cone satisfying the cancellation law. In this paper the author proves that if \(f:M\to S\) is a solution of the Jensen functional equation, then it is a solution of the following equation \[ 3(b-1) f\biggl(\frac{x+y+z}{3}\biggr)+ f(x)+f(y)+f(z)= b\Biggl[f\biggl(\frac{x+y}{2}\biggr)+ f\biggl(\frac{y+z}{2}\biggr)+ f\biggl(\frac{z+x}{2}\biggr)\Biggr] \] and conversely, if \(b\geq 1, b\neq 4\) and \(f:M\to S\) is a solution of the equation above, then \(f\) is a solution of the Jensen functional equation. This result is based on works of \textit{Y. W. Lee} [J. Math. Anal. Appl. 270, No. 2, 590--601(2002; Zbl 1007.39026)] and \textit{T. Trif} [J. Math. Anal. Appl. 250, No. 2, 579--588 (2000; Zbl 0964.39027)]. He also shows that the function \(f\) satisfies the equation above for \(b=4\) if and only if it fullfills the system of functional equations \[ \begin{aligned} f(x+y)+f(-x)+f(-y)&= f(-x-y)+f(x)+f(y),\\ 2f(0)+f(x+y)+f(x-y)&= 2f(x)+f(y)+f(-y).\end{aligned} \]
system of functional equations, Jensen functional equation, abstract covex cone, Abelian group, Systems of functional equations and inequalities, additive and quadratic functions, Functional equations for functions with more general domains and/or ranges, multifunctions
system of functional equations, Jensen functional equation, abstract covex cone, Abelian group, Systems of functional equations and inequalities, additive and quadratic functions, Functional equations for functions with more general domains and/or ranges, multifunctions
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 2 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Average | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Average | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
