Paper 4, Section II, E

Dynamical Systems
Part II, 2020

(a) Let F:IIF: I \rightarrow I be a continuous map defined on an interval IRI \subset \mathbb{R}. Define what it means (i) for FF to have a horseshoe and (ii) for FF to be chaotic. [Glendinning's definition should be used throughout this question.]

(b) Consider the map defined on the interval [1,1][-1,1] by

F(x)=1μxF(x)=1-\mu|x|

with 0<μ20<\mu \leqslant 2.

(i) Sketch F(x)F(x) and F2(x)F^{2}(x) for a case when 0<μ<10<\mu<1 and a case when 1<μ<21<\mu<2.

(ii) Describe fully the long term dynamics for 0<μ<10<\mu<1. What happens for μ=1\mu=1 ?

(iii) When does FF have a horseshoe? When does F2F^{2} have a horseshoe?

(iv) For what values of μ\mu is the map FF chaotic?