1 Al. (i) Let X be a set and SCP(X) a set of subsets of X. (a) Define what is meant by the o-algebra generated by S. (b)
Posted: Mon May 02, 2022 8:53 pm
1 Al. (i) Let X be a set and SCP(X) a set of subsets of X. (a) Define what is meant by the o-algebra generated by S. (b) Show that the set of all intervals with rational endpoints is a set of gener- ators for the o-algebra of Borel subsets B(R). (ii) Consider the interval (0.1) CR. Every x € (0,1) has a decimal expansion 1 = 0.222.23..., where x; € {0,1,...,9}. As in the course we will not allow the expansion to eventually end in repeated 9s to avoid ambiguity. Let B be the set of points in (0,1) whose decimal expansion contains infinitely many 5s. Show that B is a Borel set. 5