Fundamentals of Mathematics - Fall 2017

Lectures

Syllabus

Syllabus

Books

Links

Handouts

These are modified versions of DZB's handouts.
  1. HO01 - Propositions (.tex)
  2. HO02 - Proof Techniques and Divisibility (.tex)
  3. HO03 - Induction (.tex)
  4. HO04 - Sets (.tex)
  5. HO05 - Indexed Unions
  6. HO06 - Indexed Union Proofs
  7. HO07 - Introduction to Functions
  8. HO08 - Injections and Surjections
  9. HO09 - Images
  10. HO10 - Images Fixing Hypotheses
  11. HO11 - Compositions of Functions
  12. HO12 - Bijections
  13. HO11 - Countability
  14. Equivalence Relations
  15. Binary Operations

Exams

Practice Exam 01
solutions
Exam 01
solutions
Exam 02 (Wednesday, November 15th) solutions
John Voight's Fall 2012 Exams and Solutions
John Voight's Fall 2011 Exams and Solutions `
Jonathan Sand's Spring 2017 Exams and Solutions
Practice for Final

Homework

Typos and misprints can occur, so if you have any questions let me know.
Homework 01 (.tex)
due: Friday, September 1st, 2017                          

Homework 02 (.tex)
due: Friday, September 8th, 2017
solutions
Homework 03 (.tex)
due: Monday, September 18th, 2017
solutions
Homework 04 (.tex)
due: Monday, September 25th, 2017
corrections due: Monday, October 2nd 2017
solutions
Homework 05 (.tex)
due: Friday, September 29th, 2017
corrections due: Friday, October 6th, 2017
solutions
Homework 06 (.tex)
due: Friday, October 6th, 2017
corrections due: Monday, October 23rd, 2017
solutions
Homework 07 (.tex)
due: Monday, October 16th, 2017
corrections due: Monday, November 6th
solutions
Extra Credit (applied to next exam)
comes from discussion at Lecture 15: 41m and 49s - 
due: Monday, November 6th, 2017

Homework 08 (.tex)
due: Monday, October 30th , 2017
corrections due: Friday, November 10th
solutions
Homework 09 (.tex)
due: Monday, November 6th, 2017
corrections due: Monday, November 27th
solutions
Homework 10 (.tex)
due: Monday, November 27th
solutions
Homework 11:
If you scored less than 8/10 on problem 3 of exam 2:
  • Lakins 4.2: 11, 16, 18
If you scored less than 8/10 on problem 4 of exam 2:
  • Sets Handout, section 2: 1,3,4 (numbering as on the current version posted on the webpage)
If you scored less than 8/10 on problem 5 of exam 2:
  • Induction handout, section 2: 11, 12
  • Lakins 3.1: 6, 11
I am not going to be emailing individual scores over break. If you didn't show up to class on Friday before break then make your best guess based on the posted solutions or wait until class on Monday.
due: Friday, December 1st, 2017
no corrections.

Homework 12 (.tex)
due: Monday, December 4th, 2017
solutions
Homework 13: (.tex)
due: Friday, December 8th, 2017 solutions

Lectures

Lecture 1 (Monday, August 28th, 2017): Propositions and Formulae Lakins 1.1
Lecture 2 (Wednesday, August 30th, 2017): Propositional Calculus/Boolean Algebra
Lakins 1.1
De Morgan Biography
Lecture 3 (Friday, September 1st, 2017): Quantifiers
Lakins 1.1
Lecture 4 (Wednesday, September 6th, 2017): Implication
Lakins 1.1
Lecture 5 (Friday, September 8th, 2017): Axioms; Groups; Rings
Hardest class of the semester.

Lakins 5.1 pg 102 talks about binary operations briefly but not in a context that is useful for you guys at this stage. We introduce binary operations as a "rule" which allow us to talk about things like addition and multiplication on sets.

Ring axioms not covered in Lakins but needed to talk about the integers rigorously.'

Long Term Goal: prove that the integers are an integral domain.

History of Ring Theory
History of Group Theory

Milestone:
We can talk about equivalence relations on universes.

The relations we develop here will be important for modular arithmetic in Lecture 26.
Lecture 6 (Monday, September 11th, 2017): Divisibility in Rings
Not in Lakins but very important as it allows us to build lots of examples.
Lecture 7 (Wednesday, September 13th, 2017): Methods of Proof
Lakins 2.1, 2.2, 2.3
Review Day (Friday, September 15th, 2017)

Lecture 8 (Monday, September 18th, 2017): Uniqueness as a tool
End of section 2
Lecture 9 (Wednesday, September 20th, 2017): Review of Homework 03 - Working with Groups and Special Primes
Lakins 7.2.0ish (Equivalence relations -- as formulas, not as sets)
but not 7.2.1 (Equivalence classes)


Lecture 10 (Friday, September 22nd, 2017): Induction
Lakins 3.1

Milestone: we can prove this:
Lakins 6.2.1 (Euclidean Algorithm): Fix m. For every n there exists some a and r with 0<r<m such that
    n = a*m + r.

It is called an algorithm because it is division with remainder.
Lecture 11 (Monday, September 25th, 2017): Dedekind-Peano Axioms, More Induction
Dedekind biography
Lecture 12 (Wednesday, September 27th, 2017): Introduction to Strong Induction
Lakins 3.2
Lakins 6.3 (the fundamental theorem of arithmetic)
Lecture 13 (Friday, September 29th, 2017): Strong and Weak Induction Equivalence, Peano Arithmetic
see Exercise 3.2.5 in Lakins

Milestone: we can now define the integers rigorously and prove that they are an integral domain

Milestone: we can now define x<y for integers rigorously
Lecture 14 (Monday, October 2nd, 2017): Signatures, Formulas, Structures, Theories, and Models
Not in Lakins but needed to refine Exercise 3.2.5

Milestone:
We are now talking about what we are assuming to prove things.

Review Day (Friday, October 6th, 2017):

Exam Day (Wednesday, October 11th, 2017)
Chapters 1 and 2
Lecture 15: (Friday, October 13th, 2017) Dedekind-Peano vs Peano Arithmetic shows Exercise 3.2.5 of Lakins is misguided

(PA and Dedekind-Peano omitted in the book)
Lecture 16 (Monday, October 23rd, 2017) : Some Famous Summation Formulas
Any Calculus I book
Lecture 17 (Wednesday, October 18th, 2017): Binomial Theorem and Ordering Lakins 6.1.2 (the well-ordering principle)

Partial orders are not covered in this book
Lecture 18 (with Puck Romback!  Friday, October 20th, 2017): Set Operations
Lakins 4.1

Cantor biography
Lecture 19 (Monday, October 23rd, 2017 ): Cartesian Products and Power Sets Lakins 4.2
History of Sets
Lecture 20 (Wenesday, October 25th, 2017): Infinite Intersections and the Least Upper Bound Property Lakins 4.3

To show certain infinite intersections are empty one needs the Archimedean property. This is implied by the existence of least upper bounds and greatest lower bounds of the real numbers. To talk about why this works we are essentially discussing the construction of the real numbers and Dedekind cuts (which defined real numbers as breaking points between collections of rational numbers)

Archimedes Biography
Lecture 21 (with Jonathan Sands! Friday, October 27th, 2017): Indexed Sets (Examples) Lakins 4.3
Lecture 22 (Monday, October 30th, 2017): Indexed Sets (Generalities) Lakins 4.3
Lecture 23 (Wednesday, November 1st, 2017): Functions Lakins 5.1, 5.5

the history of the function concept
Lecture 24 (with Christelle Vincent! Friday, November 3rd, 2017): Injectivity and Surjectivity Lakin 5.3
Lecture 25 (Monday, November 6th, 2017): Quotients Lakins 7.2
Lecture 26 (Wednesday, November 8th, 2017): More Quotients Lakins 7.2.1  (Equivalence Classes)
Lakins 6.4, 6.5 (Congruences)

Two constructions where equivalence classes matter:
*the construction of the rationals as a quotient
*Cantor's construction of the real numbers
Lecture 27 (Friday, November 10th, 2017): Compositions, Left Inverses, Right Inverses Lakins: 5.2, 5.4
Exam 2

Lecture 28 (Friday, November 16th, 2017): Left/Right Inverses and the Axiom of Choice Zemelo-Frankel Choice (ZFC) Axioms (the official we use in modern mathematics)

VSauce video on Banach-Tarski (a strange consequence of the Axiom of Choice)

The Axiom of Choice

Zorn's Lemma (a statement which is equivalent to the Axiom of choice) appears everywhere in analysis and abstract algebra and is a fundamental tool for modern mathematics. Here are some notes for people who are interesting in seeing where this road goes:
Keith Conrad's notes on Zorn's Lemma

Some Remarks on Keith Conrad's webpage:
Keith Conrad (UConn) has put together an amazing collection of notes on various topics which provide very good expositions to often difficult topics for first time readers. If you find yourself stuck on something these notes can be a great resource.
Lecture 29 (Monday, November 27th, 2017): Different Size Infinities (Cardinality) History of Infinity

Book of Proof: Chapter 13
Lecture 30 (Wednesday November 29th, 2017): Uncountable Infinity Book of Proof: Chapter 13
Lecture 31 (Friday, December 1st, 2017): Uncountable Infinity = Power Set of Naturals Book of Proof: Chapter 13
Lecture 32 (Monday, December 4th, 2017): Cantor-Bernstein-Schroder
Lecture 33 videos (online): Pidgeonhole Principle