Paper 3 , Section II, J
Part II, 2015
(a) Let be a measure space. What does it mean to say that is a measure-preserving transformation? What does it mean to say that a set is invariant under ? Show that the class of invariant sets forms a -algebra.
(b) Take to be with Lebesgue measure on its Borel -algebra. Show that the baker's map defined by
is measure-preserving.
(c) Describe in detail the construction of the canonical model for sequences of independent random variables having a given distribution .
Define the Bernoulli shift map and prove it is a measure-preserving ergodic transformation.
[You may use without proof other results concerning sequences of independent random variables proved in the course, provided you state these clearly.]