Math 354 Set Theory, Spring 2011
Contents (copied from Moodle):
Syllabus
List of Topics
HW assignments
HW solutions
Scorpling Flugs
Caro Brighouse |
Ramin Naimi |
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
Introduction
Sets, Classes and the Set Theoretic Heirarchy
The Axiomatic Method
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
Relations and Functions
Ordered Pairs
Relations
Functions
The Axiom of Choice
Infinite Cartesian Products (tentative)
Equivalence Relations
Ordering Relations
The Natural Numbers
Inductive Sets
Peano's Postulates
Recursion on Omega
Arithmetic
Ordering on Omega
Tentative: The construction of the Reals
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
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 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
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 then
.
Second hint (try again to do the problem before reading this):
is
a subset of
,
so it's an element of ... .
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; 21=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 "
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 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.
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 ,
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.)
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.