B3.17

Dynamical Systems
Part II, 2003

Let f:IIf: I \rightarrow I be a continuous one-dimensional map of the interval IRI \subset \mathbb{R}. Explain what is meant by saying (a) that the map ff is topologically transitive, and (b) that the map ff has a horseshoe.

Consider the tent map defined on the interval [0,1][0,1] by

f(x)={μx0x<12μ(1x)12x1f(x)= \begin{cases}\mu x & 0 \leqslant x<\frac{1}{2} \\ \mu(1-x) & \frac{1}{2} \leqslant x \leqslant 1\end{cases}

for 1<μ21<\mu \leqslant 2. Show that if μ>2\mu>\sqrt{2} then this map is topologically transitive, and also that f2f^{2} has a horseshoe.