Abstract
Michael Fisher once studied the solution of the equation f(f(x))=x 2−2. We offer solutions to the general equation f(f(x))=h(x) in the form f(x)=g(ag −1(x)) where a is in general a complex number. This leads to solving duplication formulas for g(x). For the case h(x)=x 2−2, the solution is readily found, while the h(x)=x 2+2 case is challenging. The solution to these types of equations can be related to differential equations.
Similar content being viewed by others
REFERENCES
Fisher, The iterated equation g(g(x))=x 2-2, private communication.
S. Ulam and J. Von Neumann, On combinations of stochastic and deterministic processes; Preliminary report, Bulletin of the AMS, 1120(1947).
A. R. Brown, On solving nonlinear functional finite difference, composition, and iterated equations, Fractals 7:277–282 (1999)
N. H. Abel, Oeuvres Completes, Christiania: Grundahl. 1881, Vol. 2, L. Sylow and S. Lie, eds. (Johnson Reprint, New York, 1988).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Brown, B.A., Brown, A.R. & Shlesinger, M.F. Solutions of Doubly and Higher Order Iterated Equations. Journal of Statistical Physics 110, 1087–1097 (2003). https://doi.org/10.1023/A:1022144826671
Issue Date:
DOI: https://doi.org/10.1023/A:1022144826671