Stability of the Jensen-type functional equation in -algebras: a fixed point approach.
Stability of the Lobacevski equation.
Stability of trigonometric functional equations in generalized functions.
Stability problem of Ulam for Euler-Lagrange quadratic mappings.
Stability problems of quintic mappings in quasi--normed spaces.
Stability results for some functional equations of quadratic-type.
Stability type results concerning the fundamental equation of information of multiplicative type
The paper deals with the stability of the fundamental equation of information of multiplicative type. It is proved that the equation in question is stable in the sense of Hyers and Ulam under some assumptions. This result is applied to prove the stability of a system of functional equations that characterizes the recursive measures of information of multiplicative type.
Stable solutions to homogeneous difference-differential equations with constant coefficients: Analytical instruments and an application to monetary theory
In economic systems, reactions to external shocks often come with a delay. On the other hand, agents try to anticipate future developments. Both can lead to difference-differential equations with an advancing argument. These are more difficult to handle than either difference or differential equations, but they have the merit of added realism and increased credibility. This paper generalizes a model from monetary economics by von Kalckreuth and Schröder. Working out its stability properties, we...
Standard threads and distributivity.
Strictly decreasing solutions of a class of iterative equations on the unit circle.
Strictly quadratic functional equations on quasigroups. I.
Struktur linearer Funktionalgleichungen im Zusammenhang mit dem Abelschen Theorem.
Studie o funkcinálních rovnicích
Sub Additive Measures of Relative Information and Inaccuracy.
Subadditive functions and partial converses of Minkowski's and Mulholland's inequalities
Let ϕ be an arbitrary bijection of . We prove that if the two-place function is subadditive in then must be a convex homeomorphism of . This is a partial converse of Mulholland’s inequality. Some new properties of subadditive bijections of are also given. We apply the above results to obtain several converses of Minkowski’s inequality.
Subadditive functions on modules and subgroups of abelian groups.
Subgroups of the Clifford group.
Subgroups of the group Zn and a generalization of the Golab-Schinzel functional equation.
Sublinear Functions on R.
Submultiplicative functions and operator inequalities
Let T: C¹(ℝ) → C(ℝ) be an operator satisfying the “chain rule inequality” T(f∘g) ≤ (Tf)∘g⋅Tg, f,g ∈ C¹(ℝ). Imposing a weak continuity and a non-degeneracy condition on T, we determine the form of all maps T satisfying this inequality together with T(-Id)(0) < 0. They have the form Tf = ⎧ , f’ ≥ 0, ⎨ ⎩ , f’ < 0, with p > 0, H ∈ C(ℝ), A ≥ 1. For A = 1, these are just the solutions of the chain rule operator equation. To prove this, we characterize the submultiplicative, measurable functions...