Results 61 to 70 of about 505 (94)

Stability and hyperstability of a quadratic functional equation and a characterization of inner product spaces

Demonstratio Mathematica, 2018
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 ...
Kim Gwang Hui, El-Fassi Iz-iddine, Park Choonkil   +2 more
doaj   +1 more source

Stability of an additive-quadratic functional equation in modular spaces

Open Mathematics
Using the direct method, we prove the Hyers-Ulam-Rassias stability of the following functional equation: ϕ(x+y,z+w)+ϕ(x−y,z−w)−2ϕ(x,z)−2ϕ(x,w)=0\phi \left(x+y,z+w)+\phi \left(x-y,z-w)-2\phi \left(x,z)-2\phi \left(x,w)=0 in ρ\rho -complete convex modular ...
Baza Abderrahman, Rossafi Mohamed, Park Choonkil, Donganont Mana   +3 more
doaj   +1 more source

Intuitionistic fuzzy almost Cauchy–Jensen mappings

Demonstratio Mathematica, 2016
In this paper, we first investigate the Hyers–Ulam stability of the generalized Cauchy–Jensen functional equation of p-variable f(∑i=1paixi)=∑i=1paif(xi)$f\left(\sum\nolimits_{i = 1}^p {a_i x_i } \right) = \sum\nolimits_{i = 1}^p {a_i f(x_i )}$ in an ...
Gordji M. E., Abbaszadeh S.
doaj   +1 more source

Orthogonal stability of mixed type additive-cubic functional equations in multi-Banach spaces

Demonstratio Mathematica, 2018
In this paper, we establish the Hyers-Ulam orthogonal stability of the mixed type additive-cubic functional equation in multi-Banach spaces.
Murali Ramdoss, Pinelas Sandra, Raj Aruldass Antony   +2 more
doaj   +1 more source

On Almost Everywhere K-Additive Set-Valued Maps

Annales Mathematicae Silesianae
Let X be an Abelian group, Y be a commutative monoid, K ⊂Y be a submonoid and F : X → 2Y \ {∅} be a set-valued map. Under some additional assumptions on ideals ℐ1 in X and ℐ2 in X2, we prove that if F is ℐ2-almost everywhere K-additive, then there ...
Jabłońska Eliza
doaj   +1 more source

Orthogonal stability of the generalized quadratic functional equations in the sense of Rätz

Demonstratio Mathematica, 2019
Let (X, ⊥) be an orthogonality module in the sense of Rätz over a unital Banach algebra A and Y be a real Banach module over A. In this paper, we apply the alternative fixed point theorem for proving the Hyers-Ulam stability of the orthogonally ...
Aiemsomboon Laddawan, Sintunavarat Wutiphol   +1 more
doaj   +1 more source

Speed of Light or Composition of Velocities

Annales Mathematicae Silesianae
We analyze in our paper questions of the theory of relativity. We approach this theory from the point of view of velocities and their composition. This is where the functional equations appear.
Sablik Maciej
doaj   +1 more source

On Functions with Monotonic Differences

Annales Mathematicae Silesianae
Motivated by the Szostok problem on functions with monotonic differences (2005, 2007), we consider a-Wright convex functions as a generalization of Wright convex functions.
Rajba Teresa
doaj   +1 more source

Approximation of the multiplicatives on random multi-normed space. [PDF]

J Inequal Appl, 2017
Agarwal RP, Saadati R, Salamati A.
europepmc   +1 more source

Approximation of the generalized Cauchy-Jensen functional equation in C ∗ -algebras. [PDF]

J Inequal Appl, 2018
Kaskasem P, Klin-Eam C.
europepmc   +1 more source