Exercise 7.1

Exercise 1: Prove that every uniformly convergent sequence of bounded functions is uniformly bounded.

Answers

Let { f n } be a uniformly convergent sequence of bounded functions on a set E . For each n , there is a number M n such that | f n ( x ) | < M n for all x E . By Theorem 7.8, there is an integer N such that | f n ( x ) f N ( x ) | < 1 if n N for all x E . Let M = max { M 1 , , M N } . Then for n N and x E we have | f n ( x ) | < M + 1 , and for n N and x E we have

| f n ( x ) | | f n ( x ) f N ( x ) | + | f N ( x ) | < M + 1 .

That is, the f n are uniformly bounded by M + 1 in E.

User profile picture
2023-08-07 00:00
Comments