Math 354 Set Theory, Spring 2011

Contents (copied from Moodle):

Syllabus
List of Topics
HW assignments
HW solutions
Scorpling Flugs


Course syllabus and policies


Instructors

 

Caro Brighouse
Office: Johnson 302
Office Hours: MW: 11:30-12:30, W: 1:30-2:30 and by appintment.
Phone: (323) 259-2588
Email: brighous at oxy.edu

Ramin Naimi
Office: Fowler 317
Office Hours: Posted at: faculty.oxy.edu/rnaimi
Phone: (323) 259-2550
Email: rnaimi at oxy.edu
 



Class Meetings: MWF 9:30-10:25, Fowler 301.

Text: Elements of Set Theory, by H. Enderton. We hope to cover most of the sections in Chapters 1-4 and 6, and maybe some from chapters 7, 8.

Homework: HW will be assigned in every class meeting, due at the next class meeting. We encourage you to work with your classmates and/or get help from us or the CAE on problems you can't do. But be honest with yourself; after figuring out how to do a problem, ask yourself: "Will I be able to do this problem on my own if it's on the exam?" To find out, turn in your own work: write it up without looking at the book or at any notes. The purpose of HW is not for us to evaluate you, but for you to learn the material and evaluate yourself. We won't have enough time to grade too many of the assigned problems. Those that get graded will be graded strictly, but the scores will not be recorded. Instead, as long as you show a sincere effort on the whole assignment, you will receive full credit for that assignment. Doing HW is essential to learning mathematics -- there is no way around it. You should spend at least two to three hours on homework every other day.

Midterms: There will be two exams, on the following dates (subject to change with prior notice): W 2/16, and W 3/30.

Final : The final exam date and time is determined by the Registrar's Office (www.oxy.edu/Registrar.xml). Please check to make sure you do not have any time conflicts with this date and time (or any early travel plans); we will not give early or late finals. The final exam will cover all topics covered during the semester.

Make-ups: No make-up exams will be given. If you miss a midterm with a valid excuse (e.g., a medical reason), and provide documentation for it, that midterm will simply not count for you—instead, your other midterm and final exam will count proportionally more. This policy does not apply to the final exam.

Grading: Your grade for the semester will be computed as follows:
Homework 5% , Midterms 50% , Final 45%.

Attendance: You are responsible for everything that goes on in every class meeting, such as announcements, handouts, taught topics that are not in the class notes, etc. This means even if you miss a class for a valid reason, it is your responsibility to contact one of us and find out what you missed. We may or may not decide to count attendance as part of your grade; if we do, we will let you know in advance; it will count as a small part of the 5% for homework.

E-mail: When necessary, we will make announcements via the class mailing list, instead of in the classroom. You are expected to check your email at least once a day. You are encouraged to use our class email list, math354-L@oxy.edu, to send messages to everyone in the class.

Academic Honesty: We feel strongly about protecting honest and hard-working students against unfair and dishonest actions sometimes committed by a few. We won't give warnings; we will refer all suspicious cases to the Judicial Examiner without hesitation.

Students with learning disability: Please see one of us and the CAE to arrange for any special needs.
 

Last modified: Wednesday, March 2, 2011, 04:19 PM

 


Detailed Course Topics

  1. Introduction

    Sets, Classes and the Set Theoretic Heirarchy

    The Axiomatic Method

  2. Axioms and Operations

    Axioms 1-6:

    Extensionality Axiom, Empty Set Axiom, Pairing Axiom, Union Axiom, Power Set Axiom, Subset Axioms.

    Arbitrary Unions and Intersections

    Algebra of sets

  3. Relations and Functions

    Ordered Pairs

    Relations

    Functions

    The Axiom of Choice

    Infinite Cartesian Products (tentative)

    Equivalence Relations

    Ordering Relations

  4. The Natural Numbers

    Inductive Sets

    Peano's Postulates

    Recursion on Omega

    Arithmetic

    Ordering on Omega

  5. Tentative: The construction of the Reals

  6. Cardinal Numbers and the Axiom of Choice

    Equinumerosity

    Finite Sets

    Cardinal Arithmetic

    Ordering Cardinal Numbers

    The Axiom of Choice

    Countable Sets

    Arithmetic of Infinite Cardinals

    The Continuum Hypothesis

  7. Ordering and Ordinals

    Partial Orderings

    Well Orderings

    Replacement Axioms

    Epsilon Images

    Isomorphisms

    Ordinal Numbers

    Rank

Last modified: Wednesday, March 2, 2011, 04:19 PM


HW assignments

  • HW 1, due F 1/21: Read: P. 1-16. Do: Exercises 1-4 (p.6)

  • HW 2, Due 1/24. Read up to page 26. Do p9 5-7, p.26 1-4. (For #7, do V_3 only; skip V_4).
     

  • HW 3 Due 1/26. Page 33 questions 26,28,30, Page 26 Questions 5,6,7.

  • HW4 due 1/28 Page 26, 8,9,10 (10 is done in the appendix, but try to do it yourself) p33 29,31

  • HW5 Due 1/31 p 32 12,13,17,21,22 and 34.35 just for fun. You will need to look up the definition of relative complement of A in B.

  • HW6 due W 2/2: P. 32-34, 15,20,24,36,38

  • HW 7, due F 2/4: Do the following problems on Scorpling Flugs

  •  Problems on Scorpling FlugsResource

  •  Class handout on Scorpling FlugsPDF document

  • There's an error on the solutions to HW 6, Scorpling flugs. 3b-- of course every set is a subset of itself!!

  • HW 8, due M 2/7: Read 36-38. Do p.38: 1, 2, 4.
     

  • HW 9, due W 2/9: Read p.39-41. Do: First do the "warm-up" problems listed below. Then do p.41: 6; p.38: 3, 5a. Hint for 5a (don't read this hint until after you've already tried your best to do the problem): Show if \small D \subseteq E  then \small D \times F \subseteq E \times F . Second hint (try again to do the problem before reading this): \small \{x\} \times B is a subset of \small A \times B  , so it's an element of ... .

  •  Warm-up problems for HW 9Resource

  • HW 10, due F 2/11. Read p.42-44. Do: p.52: 11, 16, 18, 21.

  • HW 11, due M 2/14: Read p.45-47. Do: p.53: 19, 22ab, 23.

  • Midterm 1, W 2/16: Will cover HWs 1-10 and their corresponding sections. You should also know all definitions, as well as the following proofs that are in the book: prove that the sets defined in the definition on p. 44 are sets (inverse, composition, restriction, image); prove that dom R and ran R are sets. prove <x,y> is a set; prove <x,y> = <u,v> iff x=u & y=v; prove the laws and identities on p.28.
     

  • HW 12, due F 2/18: Read p.48. Do: p.53: 24, 25.

  • Midterm 1.1, W 2/23: Only one problem, to replace problem #4(b,c) of Midterm 1. Will cover HWs 1-10 and their corresponding sections.

  • HW 13, due 2/23: Make sure to read the book's formulation of Axiom of Choice on page 49 and try to see how it's related to our formulation given in class (see (4) on page 151). Do: p.53: 26, 29.

  • HW 14, Due F 2/25. P61: 33, 34 (prove or give a counterexample in each case), 35.

  • HW 15, Due Monday 2/28. P 61 37,38, and the following question:
    Look at Theorem 3M on page 56. Then read the next paragraph.
    Also note the definition of a “binary relation on A” on page 42.
    Construct a relation R on the natural numbers that is symmetric and transitive on the natural numbers, an equivalence relation on the field of R, but is not an equivalence relation on the natural numbers.

  • HW 16: Due Wed 3/2. Page 62, 40, page 64, 43, 44.

  • HW17 Page 64: 45, Page 172: 1,2. Due Friday 3/4

  • HW 18 Pg 88: 30, 31, 32. Read "What Numbers Could Not Be" for Monday 3/12.

  • HW 19, due Friday 3/18: Read: p.70-73. Do: p.89: 33c; p.73: 2, 4, 6.
    Also do the following problem (it may be better to do it before the above problems):
    (i) Give three distinct transitive sets, each of which has exactly four elements.

  • HW 20, due Monday 3/21: Read p.73-78; may skip proof of Recursion Theorem. Do: p. 89: 38, 40; p. 78: 8. Check HW solutions folder for solutions.

  • HW 21, due Wednesday 3/23: Read p.79-82. Do: p.83: 13-15. Hints/suggestions: 13: Prove the contrapositive. 14: Prove by induction; use theorems in the book; and prove 1+1=2; 2\cdot1=2.

  • HW 22, due F 3/25: Read p.83-85. Do: p.88: 18, 22, 23. Hint for 22 and 23 : Use induction.

  • HW 23, due M 3/28: Read: p.86-87. Do: 26, 37a. Also, give a detailed proof of Corollary 4Q (p.87).

  • Midterm 2, W 4/30. The midterm covers HWs 11-22.
     

  • HW 24, due F 4/1: p.88: Do: 24, 28, 37b. For 37b, just construct the desired bijection; no need to prove it is a bijection. Also, prove the theorem "Well Ordering of \omega" without looking at the proof in the book.

  • HW25 Due Monday 4/4. Page 101, 4, page 133, 1 and 5. Also, using just the natural numbers (and set theoretic and associated notation), write the natural number 1, the integer 1 and the rational number 1.

  • HW26 1. a.Show that the open interval of reals, (0,1), is equinumerous to the positive reals, (0,infinity). Can you find a map that takes rationals to rationals.

    b. Show that the set of all ordered triples <x,y,z> of natural numbers is equinumerous to the set of natural numbers.

    c. Show that the set of finite strings from the English alphabet is equinumerous to the set of natural numbers.

    P. 138, 6,7. One way to do 7 will involve the well ordering principle. Another way will use the axiom of choice. You get one piece of candy for using the axiom of choice, and two for using the well ordering principle (do it both ways and you get three!), unless your name is "Ramin", in which case you get no candy, but some goat cheese instead!

  •  HW 27 Due Friday 4/8. Also read pages 133-138. You should look at the proofs of theorems that we didn't prove in class, and make sure you can follow them.Word document

  • HW 28 Due Monday 4/11. Read pages 138-144
    On Page 141-142 there are a number of facts about cardinal arithmetic. Prove that a) Aleph zero + Aleph zero = Aleph zero, b) 3.aleph zero = aleph zero (. here is cardinal multiplication), and c) That cardinal addition is associative.
    Also do p.138, 8 and p.144, 13

  • HW29. Due Wednesday 4/13. Page 150 15, 17. Also, Justify example 2 on Page 146, and re-write Enderton's proof of the well defined-ness of "A is dominated by B" at the bottom of page 145 so that it would satisfy Ramin or me.

    Note: We haven't proved the Schroder Bernstein Theorem, but you may want to remind yourself of what it says, so if necessary you can use it.

  •  Homework #30Word document

  • HW 31, due M 4/18: Read p. 151, the bottom 6 lines on p.154, all of p.155, and the statement of Theorem 6N. (Zorn's Lemma is optional. Also, recommended but not required: read some of the proofs on p.152.) Do: P. 158: 18, 19, 24(sums only; no products).
     

  • HW 32, due W 4/20: Read p. 159. Learn the proof of Corollary 6P for the final exam. Do: p.161: 27. Also do these extra problems:
    (i) Prove the function g in the proof of Corollary 6P is one-to-one.
    (ii) Prove, without using Theorem 6Q, that if A and B are each equinumerous with\omega , then their union is countable.
     

  • HW 33, due F 4/22: Read p.159, including the proof of Theorem 6Q. Do: p.161: 26, 28, 29.

  • HW 34, due M 4/25: Read p.162-165 (may skip proof of Lemma 6R). Do: p.165: 32, 34. (Optional: 35.)

  • Homework for Friday

  • Final Exam, Thursday 5/5/11, 9:00-12:00. The final exam will be cumulative, with some emphasis on material covered after our second midterm.


HW_solutions

Scorpling-Flugs-p1.pdf