Given a (not necessarily unitary) character µ: G→(C\{0},·) of a group G we find the solutions
g: G→ C of the following version of d'Alembert's functional equation g (xy)+ µ (y) g (xy− 1) …

Abstract Let (G,+) be a locally compact abelian Hausdorff group, and let μ be a regular
compactly supported complex-valued Borel measure on G such that μ (G)= 1 2. We find the …

Let G be an abelian group, CC be the field of complex numbers, α ∈ G α∈ G be any fixed
element and σ: G → G σ: G→ G be an involution. In this paper, we determine the general …

A note on a modification of Gajda’s equation Page 1 Aequat. Math. 82 (2011), 135–141 c©
The Author(s) 2011. This article is published with open access at Springerlink.com 0001-9054/11/010135-7 …

In the present paper we deal with the following generalization of the sine-cosine
equation\begin {equation*}\int f_1 (x+ yt)+ f_2 (x-y+ t) d\mu (t)= g (x) h (y)\end {equation*} for …

The present work aims to determine the solution of trigonometric functional equation f with
involution from group to field by using the properties of involution function, and the solution …

Let G be a locally compact abelian Hausdorff group, let σ σ be a continuous involution on G,
and let μ, ν μ, ν be regular, compactly supported, complex-valued Borel measures on G. We …

A generalization of Gajda’s equation on commutative topological groups Page 1 Publ. Math.
Debrecen 88/1-2 (2016), 163–176 DOI: 10.5486/PMD.2016.7311 A generalization of Gajda’s …

We discuss some trigonometric functional equations for mappings defined on a group and
taking values in the field of complex numbers. Moreover, we will present some methods …