aequationes mathematicae

, Volume 38, Issue 2–3, pp 146–154 | Cite as

A functional equation of Ih-Ching Hsu

  • John S. Lew
Research Papers


A recent note of Ih-Ching Hsu poses an unsolved problem, to wit, the general solution of the functional equation g(x1, x2) + g(φ1(x1), φ2(x2)) = g(x1, φ2(x2)) + g(φ1(x1),x2), where the φi are given functions. This short paper obtains the general solution. It gives conditions which imply that anycontinuous solution has form g1(x1) + g2(x2).

AMS (1980) subject classification

Primary 39B40 


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Copyright information

© Birkhäuser Verlag 1989

Authors and Affiliations

  • John S. Lew
    • 1
  1. 1.Mathematical Sciences Dept.IBM Research Division, T.J. Watson Research CenterYorktown HeightsUSA

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