Schedule and Homework MAT 324





Week: Aug 28
Material:
Chapter I
sections 2.1, 2.2
Homework: All exercises from sections 2.1 and 2.2 and read carefully.
Homework to be graded: Define the Lebesgue function geometrically, as in class. Show
1) f extends to a continuous function on [0,1]
2) Show that f is not differentiable at x=0.
Remarks: In general: The homework exercises will always be ALL the exercises from the sections discussed that week. Note: there is an answer section at the end of the book.


Week: Sep 4
Material:
section 2.3, 2.4
Example of a non-measurable set.
Homework: exercises from section 2.3 .
Homework to be graded: Let f(x)=x+ t mod 1, where t is irrational. The set of labels of the orbits of f is denoted by Z. Show
1) m^*(f^k(Z))=m^*(Z). Hint: proposition 2.8
2) Z is not measurable
Remarks:


Week: Sep 11
Material: 2.5, 3.1, 3.2, 3.3, 3.4
Example of a measurable set which is not Borel.
Homework: All exercises form these sections
Homework to be graded:
1) Construct an injective non measurable function f:[0,1] to R.
2) If f,g: R to R are both measurable, does this imply that also f composed with g is measurable?
Remarks:


Week: Sep 18
Material: 4.1, 4.2, 4.3
up to Theorem 4.19
Homework:
Remarks: Midterm I will be held on Oct 19 in class.
The material will be announced later. There will be a review on Oct 17.

No Homework this week


Week: Sep 25
Material: 4.3, 4.4, 4.5
Homework: Home work to be graded:
1) Let f_n be a nonnegative decreasing sequence of integrable functions with S f_n converges to 0 (The S stands for integral). Show f_n converges to 0 almost everywhere.
2) Let f, g be integrable and f bounded. Show fg is integrable. Give an example of a pair of piecewise constant functions, both integrable functions but fg is not integrable.
Remarks: Midterm I will be held on Oct 19 in class.
The material will be announced later. There will be a review on October 17.



Week: Oct 2
Material: 4.6, 5.1
Homework/Project: Homework to be graded:
Let f be a function defined on [0,1]:
on [0,1/5) f(x)=5/2 x
on [1/5, 1/2) f(x)=5/3 (x -1/2)+1
on [1/2, 1] f(x)=2x mod 1
Let h be a step function. Define a new step function by
Th(x)= sum_{y\in f^{-1}(x)} 1/Df(y) h(y)
where Df is the derivative of f.
1) Show there is a step function h_0\>0 with Th_0=h_0 and \int h_0=1
where \int means integral.
2) Show \int Th =\int h for every step function
The statement means that the total amount of sand does not change.
3) Show that for every step function h with \int h=1: T^n h converges to h_0 in L^1, i.e.
\int |T^n h-h_0| converges to 0.
4) Show hat for every integrable f with \int f=1: T^n f converges to h_0 in L^1, i.e.
\int |T^n f-h_0| converges to 0
The due date for this homework is Thursday November 3.
Remarks: Midterm I will be held on Oct 19 in class.
The material for the midterm is everything from the schedule up to and included 4.6. There will be a review on October 12



Week: Oct 9
Material: no new material
Homework:
Remarks: Midterm I will be held on Oct 19 in class.
The material for the midterm is everything from the schedule up to and included 4.6.
There will be a review on October 12. Prepare questions.


Week: Oct 16
Material: 5.1, 5.2
Homework Homework to be graded:
Do the usual exercises from the book. No homework collection for this week.
Remarks: Midterm I will be held on Oct 19 in class.
The material for the midterm is everything from the schedule up to and included 4.6.


Week: Oct 23
Material: 5.2, 5.3
Homework: 1) Construct a sequence of functions in L^2([0,1]) which is Cauchy in L^1 but not Cauchy in L^2.
2) Let K be closed subspace of L^2([0,1]). Show that the orthogonal projection onto K is a continuous linear map.
3) Show that L^2([0,1]) is dense in L^1([0,1]), i.e. for every f in L^1([0,1]) there exists a sequence of functions f_n in L^2([0,1]) such that || f_n-f||_1 to 0.
4) Show that there does not exists an inner product on L^1([0,1]) which induces the L^1-norm.
Remarks:


Week: Oct 30
Material: 6.1, 6.2, 6.3
Homework: 1) Show that the closed unit disk is in the sigma-field of the plane.
2) Show that the open unit disk is in the sigma-field of the plane.
Remarks: The average for the first midterm is 14/40. The average corresponds more or less to a B. If you got above the average you did well. If below the average you have to be more careful.


Week: Nov 6
Material: 6.4, 7.2
Homework: Give a proof of Corollary 6.11.
Remarks:
The second midterm will be held in class on Tuesday November 28
The material will be up to and included section 7.2.
There will be a review on Thursday November 23.


Week: Nov 13
Material: 7.2, 7.3
Homework: Let p >1/2. and mu_p the Bernouili measure
1) Let x=k/2^n a dyadic rational. Describe mu_p([x, x+delta x] when delta x to 0.
2) Let x=k/2^n a dyadic rational. Describe mu_p([x-delta x,x] when delta x to 0.
3) Let x in E_p. Describe mu_p([I_n] when |I_n| to 0 and I_n a dyadic interval.
4) The distribution function of mu_p is Holder. What is the optimal Holder-exponent?
Remarks: The second midterm will be held in class on Tuesday November 28
The material will be up to and included section 7.2.
There will be a review on Thursday November 23.


Week: Nov 20
Material: 7.3
Homework: For each p construct an iterated function system whose attractor is the the graph of the distribution function of the Bernoulli measure mu_p. Include a proof.
This homework is due in the week of November 28.
Remarks: The second midterm will be held in class on Tuesday November 28
The material will be up to and included section 7.2.
There will be a review on Thursday November 23.

The threshold for The Big Homework is 30/40. If you got at least 30 you do not need to do the final exam.


Week: Nov 27
Material:
Homework:
Remarks: The second midterm will be held in class on Tuesday November 28.


Week: Dec 4
Material: 7.3.4
Homework:
Remarks: Final exam:
Material: everything from the schedule up to and included 7.3.4.
Date: Dec 21
Time: 11:15-13:45
Room: Lgt Eng 154

Thursday: Review.
Average Midterm II: 26
The average corresponds more or less with a B.