ArticleOriginal scientific text
Title
The Christensen measurable solutions of a generalization of the Gołąb-Schinzel functional equation
Authors 1
Affiliations
- Institute of Mathematics, Pedagogical University of Rzeszów, Rejtana 16a, 35-310 Rzeszów, Poland
Abstract
Let K denote the set of all reals or complex numbers. Let X be a topological linear separable F-space over K. The following generalization of the result of C. G. Popa [16] is proved. Theorem. Let n be a positive integer. If a Christensen measurable function f: X → K satisfies the functional equation , then it is continuous or the set {x ∈ X : f(x) ≠ 0} is a Christensen zero set.
Keywords
Gołąb-Schinzel functional equation, Christensen measurability, F-space
Bibliography
- J. Aczél and S. Gołąb, Remarks on one-parameter subsemigroups of the affine group and their homo- and isomorphisms, Aequationes Math. 4 (1970), 1-10.
- K. Baron, On the continuous solutions of the Gołąb-Schinzel equation, Aequationes Math. 38 (1989), 155-162.
- W. Benz, The cardinality of the set of discontinuous solutions of a class of functional equations, Aequationes Math. 32 (1987), 58-62.
- N. Brillouët et J. Dhombres, Equations fonctionnelles et recherche de sous groupes, Aequationes Math. 31 (1986), 253-293.
- J. Brzdęk, Subgroups of the group
and a generalization of the Gołąb-Schinzel functional equation, Aequationes Math. 43 (1992), 59-71. - J. Brzdęk, A generalization of the Gołąb-Schinzel functional equation, Aequationes Math. 39 (1990), 268-269.
- J. Brzdęk, On the solutions of the functional equation
, Publ. Math. Debrecen 38 (1991), 175-183. - J. P. R. Christensen, Topology and Borel Structure, North-Holland Math. Stud. 10, North-Holland, 1974.
- J. P. R. Christensen, On sets of Haar measure zero in abelian Polish groups, Israel J. Math. 13 (1972), 255-260.
- P. Fischer and Z. Słodkowski, Christensen zero sets and measurable convex functions, Proc. Amer. Math. Soc. 79 (1980), 449-453.
- S. Gołąb et A. Schinzel, Sur l'équation fonctionnelle f(x+yf(x)) = f(x)f(y), Publ. Math. Debrecen 6 (1959), 113-125.
- D. Ilse, I. Lechmann und W. Schulz, Gruppoide und Funktionalgleichungen, Deutscher Verlag Wiss., Berlin, 1984.
- P. Javor, On the general solution of the functional equation f(x+yf(x)) = f(x)f(y), Aequationes Math. 1 (1968), 235-238.
- M. Kuczma, An Introduction to the Theory of Functional Equations and Inequalities, PWN and Uniw. Śląski, Warszawa-Kraków-Katowice, 1985.
- P. Plaumann und S. Strambach, Zweidimensionale Quasialgebren mit Nullteilern, Aequationes Math. 15 (1977), 249-264.
- C. G. Popa, Sur l'équation fonctionnelle f(x+yf(x)) = f(x)f(y), Ann. Polon. Math. 17 (1965), 193-198.
- W. Rudin, Real and Complex Analysis, McGraw-Hill, 1974.
- M. Sablik and P. Urban, On the solutions of the equation
, Demonstratio Math. 18 (1985), 863-867. - S. Wołodźko, Solution générale de l'équation fonctionnelle f(x+yf(x)) = f(x)f(y), Aequationes Math. 2 (1968), 12-29.