A simple functional operator.
A simultaneous system of functional inequalities and mappings which are weakly of a constant sign.
A solution of an open problem concerning Lagrangian mean-type mappings
The problem of invariance of the geometric mean in the class of Lagrangian means was considered in [Głazowska D., Matkowski J., An invariance of geometric mean with respect to Lagrangian means, J. Math. Anal. Appl., 2007, 331(2), 1187–1199], where some necessary conditions for the generators of Lagrangian means have been established. The question if all necessary conditions are also sufficient remained open. In this paper we solve this problem.
A solution to a problem of J. Schwaiger.
A special solution of the inhomogeneous Schröder equation.
A stability of the generalized sine functional equations. II.
A stochastic functional equation.
A structure theorem for sum form functional equations.
A synthesis of multidimensional judgements consistent with linear transformations.
A system of functional equations related to plurality functions. A method for the construction of the solutions.
A system on functional equations related to plurality functions. A method for the construction of the solutions. (Summary).
A theorem of the Hahn-Banach type and its applications
Let Y be a subgroup of an abelian group X and let T be a given collection of subsets of a linear space E over the rationals. Moreover, suppose that F is a subadditive set-valued function defined on X with values in T. We establish some conditions under which every additive selection of the restriction of F to Y can be extended to an additive selection of F. We also present some applications of results of this type to the stability of functional equations.
A uniqueness criterion for fractional iteration
A variant of Jessen's inequality and generalized means.
A variant of Jessen's inequality of Mercer's type for superquadratic functions.
A vector functional equation and linear differential equations.
Abel's equation and regular growth: Variations on a theme by Abel.
About solutions of a functional equation.
About the growth of entire functions solutions of linear algebraic -difference equations
Absolutely linear relations.