It would be convenient to show some work. What difficulties have you had?. For example so, .
Let the collection of finite unions of sets of the form
, when a<b ."
a. Show that is an algebra on .
b. Show that the -algebra generated by is
P( ) (the power set of ).
c. Define on by ( )=0 and (C)= for C . Show that is a premeasure on and that there is more than one measure on P( ) whose restriction to is .