1969 : A one-dimensional noninvertible map
- Christian Mira
Before the emergence of chaos in electronic circuits during the late 70s and early 80s there is an important contribution by Igor Gumowski & Christian Mira (the “Toulouse Research Group”) whose a short story was given in Ref. [1] Stimulated by a paper by C. P. Pulkin [2] who showed that in one-dimensional noninvertible map infinitely many unstable cycles may lead to bounded complex iterated sequences, Gumowski & Mira studied the piecewise-linear map [3]
![\left\{
\begin{array}{l}
x_{n+1} = ( 1 - \lambda) x_n + y_n \\[0.1cm]
y_{n+1} = y_n + f(x_n)
\end{array}
\right.
\mbox{ where }
f(x_n) =
\left|
\begin{array}{lcl}
- 2 \lambda x_n - 0.9 \lambda & & x_n < -0.5 \\[0.1cm]
\displaystyle
- \frac{\lambda x_n}{5} & \mbox{ if } & |x_n| < 0.5 \\[0.3cm]
- 2 \lambda x_n + 0.9 \lambda & & x_n > -0.5 \, .
\end{array}
\right.](local/cache-TeX/e54fe3a402a4e1af0f32d9ff15301853.png "\left\{
\begin{array}{l}
x_{n+1} = ( 1 - \lambda) x_n + y_n \\[0.1cm]
y_{n+1} = y_n + f(x_n)
\end{array}
\right.
\mbox{ where }
f(x_n) =
\left|
\begin{array}{lcl}
- 2 \lambda x_n - 0.9 \lambda & & x_n < -0.5 \\[0.1cm]
\displaystyle
- \frac{\lambda x_n}{5} & \mbox{ if } & |x_n| < 0.5 \\[0.3cm]
- 2 \lambda x_n + 0.9 \lambda & & x_n > -0.5 \, .
\end{array}
\right.")
For some 
-values, they obtained attractive limit set made of bounded cloud of points as shown in Fig. 1 (
). This could have been the first now called “chaotic” solution to a piecewise-linear map reported with an explicit picture. By these times, Gumowski & Mira indicated these types of behaviors as “Pulkin phenonmenon”. This is only ten years later that first chaotic solutions were widely investigated in
electronic circuits.
- Fig. 1. Bounded-2 chaotic attractor solution to the piecewise-linear map as published in 1969
Increasing slightly the value to 2.39, the chaotic solution observed is just before a boundary crisis unifying the two sets of points (Fig. 2).
- Fig. 2. Chaotic solution just before a boundary crisis.
- Budapest, 1968
[1] C. Mira, I. Gumowski and a Toulouse Research Group in the “prehistoric times of chaotic dynamics”, World Scientific Series in Nonlinear Science A, 39, 95-198, 2000.
[2] C. P. Pulkin, Oscillating iterated sequences (in Russian), Dokl. Akad. Nauk. SSSR, 76 (6), 1129-1132, 1950.
[3] I. Gumowski & C. Mira, Sensitivity Problems Related to Certain Bifurcations in Non-Linear Recurrence Relations, Automatica, 5, 303-317, 1969.
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MàJ . 10/05/2019