Math 415: Introduction to Real Analysis

Humboldt State University Fall 2003

 

General Information

Instructor: Walden Freedman                     Office: Library 40             Office Hours:    MWF 3:00-4:00 pm, TR 1:00-2:30 pm, or by appointment

Office Phone: 826-4763      Math Dept Phone:  826-3143        Math Dept Fax: 826-3140     E-mail: wf6@humboldt.edu

 Course Webpage: http://www.humboldt.edu/~wf6/m415/         Lecture: MWF 10:00—11:10 in Lib 56         Number of Credits: 4.0     CRN: 41795

 Required Textbook: Analysis with an Introduction to Proof, by Steven R. Lay, 3rd edition, Prentice-Hall, ISBN: 0-13-089879-1.  Chapter 1 is for you to read on your own as reference.  It covers the basic techniques of proof, covered in Math 240.   We will aim to cover chapter 2 quickly as a review of other Math 240 topics, and then cover chapters 3, 4, 8, and 5, in that order, in detail.  In particular, we will cover sections 5—7, 8 (up to page 73), 10—19, 32-34, 20-23, in that order.

 Other Resources:

·          Next to my office is the math department’s informal library.  You can find a number of additional real analysis texts to consult.

·          I have a large collection of real analysis books in my office, courtesy of Dr. C. Biles.   You are welcome to take a look.

·          Check out the real analysis links on my webpage:  http://www.humboldt.edu/~wf6/links.htm#Real Analysis

 Course Prerequisites: Math 210, 240.  Math 343 is strongly recommended.

 Course Objectives:  Knowing and understanding the main mathematical definitions used in the course; Knowing and understanding the main theorems covered in the course; Writing proofs in real analysis; knowing the central ideas and techniques of undergraduate real analysis; tackling new problems using the techniques and concepts of the course; providing the background required by graduate schools in mathematics, or applied fields.

 Exam Dates:

Midterm I: Monday, September 29

Midterm II: Wednesday, November 12

Final Exam: Friday, December 19, 10:20—12:20.  Make your travel plans accordingly. 

 

Topics

(a)   Sets and functions: Sets and elements of sets; Subsets; Equality of sets; Intervals in R; The natural numbers N, the integers Z, and rational numbers Q.   The empty set; Union, intersection, and complements of sets; Disjoint sets; Indexed families of sets and set operations on them; Symmetric difference; Ordered pairs; Cartesian products; Functions; Domain, range, and codomain; Surjective (onto) functions; Injective (one-to-one) functions; Bijections; Characteristic (indicator) functions; Action of functions on sets; Image and preimage; Composition of functions; Inverse functions; Equinumerous sets; Denumerable sets; Countable and uncountable sets; Uncountability of R

(b)    Induction: Induction; Well-ordering property of N

(c)    Ordered fields:  Fields; Commutative and distributive laws; Trichotomy, and other order laws; Ordered fields

(d)   The real number system and its topology: Upper and lower bounds; Bounded sets; Maximums and minimums of sets; Supremum and infimum; Completeness axiom; Archimedean property of R; Denseness of Q in R; Neighborhoods in R; Deleted neighborhoods; Interior and boundary points; Open and closed sets; Accumulation points; Isolated points; Closure, boundary, and interior of a set; Compact sets; Open covers and subcovers of sets; Heine-Borel Theorem; Bolzano-Weierstrass Theorem

(e)    Metric spaces: Triangle inequality; Euclidean metric; Bounded sets in metric spaces; Dense subsets; Separable metric spaces

(f)     Sequences: Convergence; Limits of sequences; Divergence; Bounded sequences; Uniqueness of limits; Boundedness of convergent sequences; Algebraic properties of limits; Infinite limits; Divergence to ±8; Monotone sequences; Monotone Convergence Theorem; Cauchy sequences; Cauchy Convergence Criterion; Contractive sequences; Subsequences; Bolzano-Weierstrass Theorem for sequences; Limsup and Liminf; Unbounded sequences

(g)   Infinite series and power series: Partial sums; Infinite series; Convergent and divergent series; Harmonic series; Cauchy criterion for series; Geometric series; Comparison test; Absolute convergence; Conditional convergence; Ratio and root tests; Integral test; Alternating series test; Rearrangements of series; Power series; Radius of convergence; Interval of convergence

(h)   Limits and continuity: Limits of functions; e-d proofs; Sequential criterion for limits of functions; Algebraic properties of limits; Right-hand and left-hand limits; Continuity of a function at a point; Continuous and discontinuous functions; Algebraic properties of continuous functions; Boundedness of functions; Continuous image of a compact set is compact; Intermediate Value Theorem; Uniform continuity

 

Course Policies

(a)    Grading: The final course grade will be determined as follows: 

Homework 50%; Two midterm exams 15% each; Final exam 20%

                  Warning! I am not a slave to any grading "formula".  For most students, the following rough guide works well:

88-100% = A,    75-87% = B,   62-74% = C,   49-61% = D,  and =48% = F

When the homework and exam scores are consistent, grading is usually not a challenge.  However, when the homework and exam scores are inconsistent, I rely on my professional judgment and not on a formula.  The bottom line is: did you learn the material, not how many points you accumulated.

(b)   Homework: I will assign homework at nearly every class meeting.  Due dates will be announced in class.  Generally, homework will be due the day of the next class meeting by 4:00 pm.  You may leave homework in the appropriate wall folder next to my office door if I am not in my office.   Do not leave homework in my mailbox in the math office.  I will not accept late homework under any circumstances; however, there will also be some opportunities to do extra credit and I will drop the lowest two homework scores.  Each homework assignment will be worth 10 points.  I may also give bonus homework points for excellence in content and presentation.  For example, well-done computer-generated graphics (if appropriate), outstanding solutions, etc.   Due to time constraints, I will not grade all problems assigned, but solutions will be available for all problems assigned. Be aware that to receive full credit on homework, you must show a good effort on all problems assigned.  Be advised that homework for this course will take a good deal of time and effort.  I advise you to begin working on a homework assignment as soon as it is assigned.  It is all too easy to fall behind with the homework, a recipe for disaster in this course: later topics and techniques absolutely require and refer to those previously covered.    Handwritten homework must be prepared neatly on clean paper, one side only. You must staple multiple pages together. I will return sloppy, disorganized work to you unread with a grade of zero. I suggest doing each assigned problem twice. Do the first draft on scratch paper.  When you know exactly how a solution goes, transcribe it neatly onto a separate sheet.  See the “guidelines for homework assignments” for how to write up your assignments.

(c)    E-mail and course webpage:  I will frequently use e-mail to contact individuals as well as the class as a whole, so please check via Records and Registration (http://www.humboldt.edu/~records/enrollment_svcs/what_registration.shtml) that your email address on file is current and usable.   Otherwise, you may miss important information during the semester.  On the course webpage http://www.humboldt.edu/~wf6/m415/ you will find a link to an MS-Excel sheet containing current homework and exam scores for the entire class.  This will enable you to keep track of your progress, and inform me of any discrepancies.  You will also be able to find a copy of this document (possibly updated), as well as other information.   Documents are in MS-Word, MS-Excel, or possibly PDF format.  Please contact me if you need help with these formats. 

 

Approximate Weekly Course Schedule

 

Week

Topics

Week #1

Aug 25—Aug 29

Basic set operations; indexed families of sets; Functions; Image and preimage; Countable sets; Induction; Strong induction; Ordered fields

Week #2

Sept 3—Sept 5

Induction; Ordered fields; Upper and lower bounds; Completeness axiom; Supremum and infimum

(Sept. 1st  is Labor Day, a holiday)

Week #3

Sept 8—Sept 12

Bounded functions; Archimedean property; Q is dense in R; e-neighborhoods; deleted neighborhoods; interior points, boundary points; Open and closed sets; unions and intersections of families of open or closed sets

Week #4

Sept 15—Sept 19

Accumulation points; closure of a set; cl S is a closed set; open covers, subcovers; compact sets

Week #5

Sept 22—Sept 26

Compact sets: Heine Borel Theorem, Bolzano-Weierstrass Theorem, Nested Intervals Theorem, Metric Spaces; Review

Week #6

Sept 29—Oct 3

Midterm I; Sequences, and convergence of sequences; uniqueness of limits; boundedness of convergent sequences; examples

Week #7

Oct 6—Oct 10

More on limits, characterization of accumulation points in terms of convergent sequences; limit theorems; Infinite limits; Monotone and Cauchy sequences

Week #8

Oct 13—Oct 17

Monotone sequences, inductively defined sequences; Cauchy sequences; proof that every Cauchy sequence is convergent; Subsequences

Week #9

Oct 20—Oct 24

Limsup and liminf ; Unbounded sequences; Convergence of infinite series

Week #10

Oct 27—Oct 31

Proof of, and examples of Comparison Test; Limit Comparison Test; Ratio Test; Absolute convergence

Week #11

Nov 3—Nov 7

Proofs of root and integral tests; Alternating series test; power series

Week #12

Nov 10—Nov 14

Review; Midterm II; Rearrangements of series

Week #13

Nov 17—Nov 21

Limits of functions; "epsilon-delta" proofs, Algebraic properties of limits; Right-hand and left-hand limits; continuous functions

Week #14

Dec 1—Dec 5

Intermediate Value Theorem; Boundedness of continuous functions;

Continuous image of a compact set is compact; Uniform continuity

Week #15

Dec 8—Dec 12

Uniform continuity; Review

General advice: 

·          Use your old Calculus text as a reference, especially for infinite sequences, series, power series, and continuity.  You will find many of the same theorems and proofs in our course, and the presentation may be easier for you to follow.  There are also some interesting problems in the exercises.

·          Read the textbook before you come to class—that way when you come to class, you will already be somewhat familiar with the ideas and we can spend our time more productively. 

·          Plan to spend about 15 hours a week studying real analysis.  This means that a good part of the learning experience in the course will happen outside the classroom.  Good study habits and a serious attitude are important. 

·          Form a group of other students with whom to study.  There are fewer better ways to increase your understanding of a subject than to try to explain it to a classmate.

·          Always read over your lecture notes, and preferably rewrite them, noting any items you didn’t fully understand, within 24 hours of the lecture. 

 Students with Disabilities: If you have a documented disability and would like to discuss academic accommodations, please contact me as soon as possible.  Our campus Student Disability Resource Center (SDRC) can assist you with the accommodation process and can be reached at extension 4678 and 5392(TDD).  The SDRC is located in House 71 (Little Apartments) off Library Circle.

 Academic Honesty:   Academic dishonesty, including cheating/plagiarism on exams and homework, is a serious offense and will not be tolerated.  University policies regarding this matter will be strictly enforced.  If you have further questions, ask your advisor or instructor for assistance.


 

Office: Library 40 (basement)  Webpage: http://www.humboldt.edu/~wf6  E-mail: wf6@humboldt.edu
Department of Mathematics, Humboldt State University, 1 Harpst St, Arcata, CA 95521  Phone: (707) 826-4763