Homework Assignments for MA6131 Real Analysis (Fall 2006)

Mon. and Wed. 2:30-3:45pm;  CU-Bldg, 641



Due

Problems

Notes

Wed. Dec. 13th

Oral presentations

Jeff 11.5 and 11.6

Don 11.7

Mon. Dec. 11th, 5pm

WRITTEN PROJECTS DUE

Oral presentations.

Mon 11.3 and 11.4

Nathan 10.1, 10.2, and 10.8

Wed. Dec. 6th

Oral presentations

Dmitry 12.1 and 12.2

Jason 11.1 and 11.2

Mon. Dec. 4th

Homework sheet

 

Wed. Nov 15th

EXAM 2

Covers material through the end of Chapter 4

Wed. Nov. 8

Ch 4: Extra Problem 5 through Extra Problem 7

 

Wed. Nov. 1

HW 6

Ch 3: 29

Ch 4: 1a through 7b (including Extra Problem 4)

Note that 1b is extra credit.

Wed. Oct. 18
HW 5

Ch 3: 18, 20, 22a,b; 25

 

EXAM 1 Mon. Oct. 9th

Material through Section 3.4

 

Monday Oct. 2
HW 4

Problems from Ch 3: 3, 4, 8, 10-12

 

Mon. Sept. 25
HW 3

Problems 44a, b, c, d from Ch 2, extra problems 2 and 3, Ch3: 1 and 2.

Test 1 will cover material through S3.4.

Wed. Sept. 13
HW 2

 

Problems from Chapter 2 listed below, 11a through 31.

 

Wed. Aug. 30

HW 1

All problems on assignment sheet from Chapter 2 up to and including 9a,b. Also, extra problem 1.

 

 

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CHAPTER 2:

3, 4b, 4c, 4d, 5b,  5d, 5e

6 should be (inf E <= sup E)

7, 9a,b; (can use results of problem 13),

extra problem 1: Write down the corresponding conditions (i) and (ii) given in problem 13, for the lim inf of x_n.

11a,b,c,d; 15,

24 (don't have to prove it), 25, 26, 27, 31

extra problem: For all a, b in R, the set of real numbers, show that ||a|-|b||<= |a-b|

44a,b,c,d;

extra problem 2: Give an example of a sequence of continuous functions which converges pointwise to a discontinuous function.

extra problem 3: Let f(x) be defined as follows: If x is irrational, then f(x) = 0. If x is rational, then if x=m/n in irreducible form then f(x) = 1/n, where n is always taken to be positive, and f(0)=1. Show that this function is continuous at every irrational point and discontinuous at every rational point.

 

CHAPTER 3:

1, 2 (hint: use proposition 1.2, p. 17),

3, 4  For problems 1-3 assume that countable additivity implies finite additivity.  Problem 4 is not trivial.

8

10, 11, 12

18 (your counterexample can assume each value more than once, but it must be measurable), 20 (use the identities to show that the sum and product of 2 simple functions are simple:  must show that the resulting functions are *single* valued),

22a,b; 25

29

 

CHAPTER 4:

1a, extra credit: 1b (function f(x) is from 1a).  Note that even if f_n are Riemann integrable which monotonically increase to a function f, the limit and integration may not be interchangeable.

extra problem 4: True or False: The characteristic function of the Cantor set is Riemann integrable. Justify (prove).

3 (hint: consider A_n = {x: f(x) > 1/n},

4 modified (Show the equivalence of the two definitions of the Lebesgue integral - assume simple functions can only take on finite values and that for each definition the measure of the space where the simple/bounded functions are not zero is finite),

5, 7a, 7b

extra problem 5: Suppose that f_n is a sequence of measurable non-negative functions on a measurable set E which converges (point-wise) almost everywhere to f. Prove that, if int_E f_n dx <= M < infinity, for all n, then f is integrable and int_E f dx <= M.

10a,

extra problem 6a: Prove that f(x) = 1/(1+x^2) is Lebesgue integrable on the real line.
             extra problem 6b: Prove that f(x) = |x|^{-1/2}(1+x^2)^{-1} is Lebesgue integrable on the real line.

12, 15a, 15b, 15c; 16

extra problem 7: Show the equivalence of the definitions of convergence in measure given in class and given in the text.


Homework 11 (pdf file)