SUNY Geneseo Department of Mathematics

Math 239 03 — Introduction to Mathematical Proof

Spring 2021
Prof. Doug Baldwin (he/him/his)

Last modified February 1, 2021

Time and Place: MWF 12:30 - 1:20, Welles 140

Instructor: Doug Baldwin
Office: South 307
Phone: 245-5659
Email: baldwin@geneseo.edu
Office Hours: Any time Monday through Friday, 8:00 AM to 5:00 PM, when I’m not committed to something else. See my Calendar for details and to make appointments electronically. You don’t need to make appointments to see me, but I recommend it in order to be sure I’ll be available. Also note that “office” hours for this course will be via video chat. We can chat at Google meeting https://meet.google.com/boo-wyaj-hcr, or you can set up another method (Zoom, Skype, telephone call, etc.) when you make an appointment.

Online Course Materials: https://www.geneseo.edu/~baldwin/math239/spring2021/course.php

Proof is the heart of modern mathematics. No mathematical claim is considered to be true unless it has been proven. Conversely, some of the most fascinating problems on the frontiers of mathematics seek proofs for various plausible-sounding but as-yet-unproven conjectures. Thus, in order to really be a mathematician, you have to be able to create proofs and read those of others. This course introduces the art of doing those things — it is the course that, more than most others, makes you into a mathematician.

Prerequisite(s): Math 222

Learning Outcomes: On completing this course, students who meet expectations will be able to…

  1. Apply the logical structure of proofs and work symbolically with connectives and quantifiers to produce logically valid, correct and clear arguments, in particular
    1. Prove equivalence of statements involving Boolean connectives
    2. Prove equivalence of statements involving logical quantifiers
  2. Perform set operations on finite and infinite collections of sets and be familiar with properties of set operations, in particular
    1. Prove properties of and relationships between sets
    2. Prove properties of and relationships between indexed families of sets
  3. Determine equivalence relations on sets and equivalence classes, in particular
    1. Determine whether a relation is an equivalence relation
    2. Identify the equivalence classes of an equivalence relation
  4. Work with functions and in particular bijections, direct and inverse images and inverse functions, in particular
    1. Construct proofs that functions are injections, surjections, and bijections
    2. Determine whether two functions are inverses of each other
  5. Construct direct and indirect proofs and proofs by induction and determine the appropriateness of each type in a particular setting. Analyze and critique proofs with respect to logic and correctness. In particular
    1. Recognize claims amenable to proof using definitions and algebraic or other relationships pertinent to the subject of the claim, and construct the corresponding proofs
    2. Recognize claims amenable to proof using the contrapositive and construct the corresponding proofs
    3. Recognize claims amenable to proof by contradiction and construct the corresponding proofs
    4. Recognize claims amenable to proof in cases and construct the corresponding proofs
    5. Recognize claims amenable to proof by induction and construct the corresponding proofs
  6. Unravel abstract definitions, create intuition-forming examples or counterexamples, and prove conjectures
  7. Write solutions to problems and proofs of theorems that meet rigorous standards based on content, organization and coherence, argument and support, and style and mechanics.

Teaching Mode

This course is designated as “hybrid.” I interpret that to mean face-to-face when possible, but with online supplements, and able to be fully online if necessary. For each topic we study, I plan to follow a pattern that begins with you reading (or maybe watching a video, etc.) about the basic ideas of that topic, then having an online and/or face-to-face discussion intended to solicit (and answer) questions about that topic and to let you practice working with it. After the discussion(s), I will produce a summary of the key ideas, and answers to key questions, and post it to Canvas. For some topics, this process will involve only one class meeting; for many it will extend over two or even three. In all cases, the schedule of face-to-face class meetings sets the pace for everything else, so you will probably find yourself working at a faster pace in this course than you would in a fully online one.

In the event that we switch to fully online instruction, we will continue the online discussions, possibly supplemented by class video meetings for people who want real-time conversation, without face-to-face meetings. All other components of the course (e.g., readings, summary notes, etc.) will continue unchanged. Note that there will not be class meetings via video when face-to-face meetings are allowed.

This design means that the course can switch from hybrid to fully online (and back) on a moment’s notice. This may be necessary if, for example, the College has to switch to online instruction for part of the semester, if I have to quarantine, etc. The course design also means that, apart from it maybe being easier to engage with learning when you do it in-person with an instructor and classmates, there is no real cost to you if you switch back and forth between taking the course as a hybrid versus taking it as purely online.

Books and Other Resources

Textbook

The (required) textbook for this course is

Ted Sundstrom, Mathematical Reasoning: Writing and Proof (Version 3)
A free PDF version of this book is available at https://scholarworks.gvsu.edu/books/24/

Videos

A collection of short videos by the author of our textbook, and designed to support a course he teaches from it, are available at https://www.youtube.com/playlist?list=PL2419488168AE7001

Another set of videos developed at Geneseo and intended to support a generic section of this course are available at https://www.geneseo.edu/proofspace

Other Resources

Materials from my spring 2019 offering of this course are available at http://www.geneseo.edu/~baldwin/math239/spring2019/course.php

Course Schedule

Note that the following dates are best estimates. They may change as our actual needs become apparent. Refer to the Web version of this syllabus for the most current information; I will keep it as up-to-date as possible.

Major course modules and activities
Feb. 1 - Feb. 3Introduction
Feb. 3 - Mar. 8Logic and Logical Statements
Mar. 8 - Apr. 5Proof Techniques
Apr. 5 - Apr. 19Sets
Apr. 19 - Apr. 28Functions
Apr. 28 - May 5Relations
May 5 - May 11Finite and Infinite Sets

Grades and Such

Grading in this course will be very different from what you are used to. The main reason for the unusual grading is that I am trying to consciously undo some of the small ways in which conventional grading unconsciously disadvantages certain students. But beyond removing disadvantages for some, I believe that what I am doing also offers significant advantages to everyone.

Key Ingredients

There are 3 main ways in which grading in this course will probably differ from what you have seen before.

The Details

“Achieving” an outcome has two components: content, i.e., what ideas you know, and depth of understanding, i.e., how thoroughly you understand those ideas. This course’s learning outcomes define both components. Generally speaking, the nouns in the outcomes correspond to content, i.e., things you will learn about. Verbs in the outcomes indicate depth of understanding, i.e., things you will understand the content well enough to do.

I will give you a numeric grade for each outcome in an exercise, based mainly on the discussion of solutions and similar problems — in other words, getting the right answers matters, but is not the only, or even the main, determiner of your grade. Grades range from 0 to 4, as follows:

General per-exercise mastery rubric
4Mastery as required by the learning outcome throughout the exercise
3Approaching the required mastery; you can describe clearly how to solve most problems arising from the exercise and why, but make mistakes in the details of doing it
2Partial mastery; you can correctly solve most problems but not explain how you solved them or why you used the methods you chose
OR you can explain and correctly solve roughly half of the problems but not more
1Initial steps towards mastery; you can begin doing the exercise but not carry solutions to completion or explain how you would do so
0No understanding of this outcome yet

Although I will grade each exercise, mastery grading isn’t about how you do on any specific one. It’s about how well you’ve achieved outcomes by the end of the course. To that end, there are two other important points about exercises and their grades:

You will “turn in” each exercise by sharing your solution with me during one of your individual meetings. During that meeting, we’ll go over your solutions and answer any questions you have about them, and we’ll also discuss how you came up with those solutions and how you would approach similar problems.

Finally, when this course ends I will give you a letter grade for it based on the numeric grades. My approach to this is that B grades (including B- and B+) indicate that you generally met the expectations of the course, A grades that you distinctly exceeded them, and grades below B- that you fell short to varying degrees. However, I won’t decide the exact cut-offs between grades until the end of the semester, when I see how grades actually worked in practice. During the semester, you can use the mastery rubric as a qualitative guideline to how you’re doing — for example, it says that 3 out of 4 points, or 75%, is “approaching the required mastery,” so an overall average of 75% should indicate that you’re doing OK but maybe not quite as well as desired. I will be happy to discuss your grades with you at any time during the semester and give you my sense of what letter grade, or range of letter grades, I think you are heading for.

Attendance

In the context of the COVID-19 pandemic, it is vital that we all do what we can to protect the health and safety of each other. If you are feeling unwell on a day that class meets, do not attend. It is better to stay home if you are not feeling well than to attend class and risk spreading illness to others. I have designed this course so that you can progress through it without some or even all of the in-person class meetings, so not coming to class won’t affect your success in it. However, please do communicate with me about absences, and contact the Dean of Students if you expect to be out for an extended period of time.

Face masks are required in all instructional spaces (including classrooms, lecture halls, and laboratories) and all common areas including residence halls and academic buildings. If you forget your mask, please pick up a disposable one before entering the classroom. Masks must be worn for the duration of class. If you do not have a mask or are unwilling to wear one, do not come to class — I cannot safely hold class unless all students are wearing face masks.

Similarly, seating in the classroom has been arranged to preserve social distancing. Please respect it, and do not rearrange classroom furniture. Try to maintain a safe distance between yourself and others at all times, including when entering and exiting classrooms.

This policy applies to me as well as to you. If there is a day when I am feeling ill, I will switch the class to online activities instead of holding an in-person class. Similarly, I will wear a mask throughout class and other meetings, and try to always keep an appropriate distance between myself and others.

Cohorts

To support social distancing during the pandemic, Geneseo is limiting classrooms to about one third of their normal occupancies. Fitting classes into the reduced-capacity classrooms often requires splitting classes into “cohorts” of students, with each cohort attending some classes and not attending others.

I have split this class into 2 cohorts, which will meet on alternating class days.

I will send a separate announcement telling you which cohort you are in. Note that to respect occupancy limits, you may only attend classes on your cohort’s day(s). On other days, you will use the online components of the course to keep up.

Working Together

Assignments in this course are fundamentally learning exercises. You are therefore welcome to help each other with them, unless specifically told otherwise in the assignment handout. However, solutions that you turn in must represent your own understanding of the solution and must be written in your own words, even if you got or gave help on the assignment.

If you use sources other than this class’s textbook or notes in order to do an assignment, you must include a comment or footnote citing those sources in your solution. Similarly, if you get help from anyone other than me you must acknowledge the helper(s) somewhere in your solution. (But note that I generally think learning from outside sources and people is a good thing, not a bad one.)

I will penalize violations of this policy. The severity of the penalty will depend on the severity of the violation.

Academic Support Services

The college provides a range of support services to help students thrive in their classes. Of these services, the one best suited to this course is the Math Learning Center. For more information, including hours and procedures for scheduling a visit, see the MLC website at https://www.geneseo.edu/math/mlc.

Other on-campus tutoring services include the Writing Learning Center (https://www.geneseo.edu/english/writing_center) and a range of department-based tutoring centers.

The SUNY-wide STAR-NY system (www.starny.org/tutoring_schedule) provides online tutoring in a wide variety of subjects.

For more information on these and other academic support services, see the Academic Support services website at https://www.geneseo.edu/academic-support-services.

Disability Accommodations

SUNY Geneseo is dedicated to providing an equitable and inclusive educational experience for all students. The Office of Accessibility will coordinate reasonable accommodations for persons with physical, emotional, or cognitive disabilities to ensure equal access to academic programs, activities, and services at Geneseo. Students with letters of accommodation should submit a letter to each faculty member and discuss their needs at the beginning of each semester. Please contact the Office of Accessibility Services for questions related to access and accommodations.

Office of Accessibility Services
Erwin Hall 22
(585) 245-5112
access@geneseo.edu
https://www.geneseo.edu/accessibility-office

In addition, if there is anything I can do to make this class or its materials easier for you to access or use, please let me know.

Geneseo offers many other services to help students succeed. For a list of some, see https://wiki.geneseo.edu/display/PROVOST/Syllabus+Resources+Related+to+Student+Success.