AMB 176

11:15-12:15PM MWF, 10:15-12:15 Th

dana.ernst@nau.edu

928.523.6852

danaernst.com

MAT 226, MAT 316, and MAT 411 with grades of C or better.

Topics in enumerative, algebraic, and geometric combinatorics, chosen at instructor’s discretion; may include advanced counting techniques, graph theory, combinatorial designs, matroids, and error-correcting codes.

There is no textbook for this course. All course content will be covered via lectures and homework.

Don’t just read it; fight it! Ask your own questions, look for your own examples, discover your own proofs. Is the hypothesis necessary? Is the converse true? What happens in the classical special case? What about the degenerate cases? Where does the proof use the hypothesis?

This course focuses on enumerative combinatorics with an introduction to generating function techniques. Here are the proposed topics:

- Eulerian numbers
- Binomial coefficients
- Generating functions
- Classical Eulerian numbers
- Eulerian polynomials
- Two important identities
- Exponential generating function

- Narayana numbers
- Catalan numbers
- Pattern-avoiding permutations
- Narayana numbers
- Dyck paths
- Planar binary trees
- Noncrossing partitions

- Partially ordered sets
- Basic definitions and terminology
- Labeled posets and P-partitions
- The shard intersection order
- The lattice of noncrossing partitions
- Absolute order and Noncrossing partitions

- Weak order, hyperplane arrangements, and the Tamari lattice
- Inversions
- The weak order
- The braid arrangement
- Euclidean hyperplane arrangements
- Products of faces and the weak order on chambers
- Set compositions
- The Tamari lattice
- Rooted planar trees and faces of the associahedron

- Refined enumeration
- The idea of a $q$-analogue
- Lattice paths by area
- Lattice paths by major index
- Euler-Mahonian distributions
- Descents and major index
- $q$-Catalan numbers
- $q$-Narayana numbers
- Dyck paths by area

An ounce of practice is worth more than tons of preaching.

As a student in this class, you have the right:

- to be confused,
- to make a mistake and to revise your thinking,
- to speak, listen, and be heard, and
- to enjoy doing mathematics.

You may encounter many defeats, but you must not be defeated.

In our classroom, diversity and individual differences are respected, appreciated, and recognized as a source of strength. Students in this class are encouraged and expected to speak up and participate during class and to carefully and respectfully listen to each other. Every member of this class *must* show respect for every other member of this class. Any attitudes or actions that are destructive to the sense of community that we strive to create are not welcome and will not be tolerated. In summary: Be good to each other. I would appreciate private responses to the following question: Are there aspects of your identity that you would like me to attend to when forming groups, and if so, how?

Students are also expected to minimize distracting behaviors. In particular, every attempt should be made to arrive to class on time. If you must arrive late or leave early, please do not disrupt class. Please turn off the ringer on your cell phone. I do not have a strict policy on the use of laptops, tablets, and cell phones. You are expected to be paying attention and engaging in class discussions. If your cell phone, etc. is interfering with your ability (or that of another student) to do this, then put it away, or I will ask you to put it away.

Don’t fear failure. Not failure, but low aim, is the crime. In great attempts it is glorious even to fail.

Reviewing material from previous courses and looking up definitions and theorems you may have forgotten is fair game. However, when it comes to completing assignments for this course, you should *not* look to resources outside the context of this course for help. That is, you should not be consulting the web, other texts, other faculty, or students outside of our course in an attempt to find solutions to the problems you are assigned. This includes Chegg and Course Hero. On the other hand, you may use each other, the textbook, me, and your own intuition. **If you feel you need additional resources, please come talk to me and we will come up with an appropriate plan of action.** Please read NAU’s Academic Integrity Policy.

You will become clever through your mistakes.

You are allowed and encouraged to work together on homework. However, each student is expected to turn in their own work. In general, late homework will *not* be accepted. However, you are allowed to turn in up to **two late homework assignments** with no questions asked. Unless you have made arrangements in advance with me, homework turned in after class will be considered late. When doing your homework, I encourage you to consult the Elements of Style for Proofs. On each homework assignment, please write (i) your name, (ii) name of course, and (iii) Homework number. You can find the list of assignments on the homework page. I reserve the right to modify the homework assignments as I see necessary.

Your homework will always be graded for completion and some subset of the problems will be graded for correctness. Problems that are graded for completeness will be worth 1 point. Problems that are graded for correctness will either be worth 2 points or 4 points depending on the level of difficulty. Generally, computational problems will be worth 2 points while problems requiring a formal proof will be worth 4 points. Each 4-point problem is subject to the following rubric:

Grade | Criteria |
---|---|

4 | This is correct and well-written mathematics! |

3 | This is a good piece of work, yet there are some mathematical errors or some writing errors that need addressing. |

2 | There is some good intuition here, but there is at least one serious flaw. |

1 | I don't understand this, but I see that you have worked on it; come see me! |

0 | I believe that you have not worked on this problem enough or you didn't submit any work. |

To compute your score on a given homework assignment, I will divide your total points by the total possible points to obtain a percent score. Each homework assignment has the same weight. Your overall homework grade will be worth 40% of your final grade.

I write one page of masterpiece to ninety-one pages of shit.

There will be two midterm exams and a cumulative final exam. Each of the exams is worth 20% of your overall grade and will consist of an in-class portion and possibly a take-home portion. The in-class portions of Exam 1 and Exam 2 are *tentatively* scheduled for ~~Wednesday, October 5~~ **Friday, October 7** (week 6) and ~~Wednesday, November 16~~ **Friday, November 18** (week 12), respectively. The final exam will be on **Monday, December 12** at 10:00AM-12:00PM. Make-up exams will only be given under extreme circumstances, as judged by me. In general, it will be best to communicate conflicts ahead of time.

The impediment to action advances action. What stands in the way becomes the way.

Regular attendance is expected and is vital to success in this course, but you will not explicitly be graded on attendance. Students can find more information about NAU’s attendance policy on the Academic Policies page. You are also expected to respectfully participate and contribute to class discussions. This includes asking relevant and meaningful questions to both the instructor and your peers in class and on our Discord server.

I must not fear.

Fear is the mind-killer.

Fear is the little-death that brings total obliteration.

I will face my fear.

I will permit it to pass over me and through me.

And when it has gone past I will turn the inner eye to see its path.

Where the fear has gone there will be nothing.

Only I will remain.

The only thing I will award extra credit for is finding typos on course materials (e.g., textbook, exams, syllabus, webpage). This includes broken links on the webpage. However, it does not include the placement of commas and such. If you find a typo, I will add one percentage point to your next exam. You can earn at most two percentage points per exam and at most five percentage points over the course of the semester. They’re is a typo right here.

In summary, your final grade will be determined by your scores in the following categories.

Category | Weight | Notes |
---|---|---|

Homework | 40% | See above for requirements |

Exam 1 | 20% | In-class portion on October 7, possible take-home portion |

Exam 2 | 20% | In-class portion on November 18, possible take-home portion |

Final Exam | 20% | In-class portion on December 12, possible take-home portion |

It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because there is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid souls who neither know victory nor defeat.

You are responsible for knowing and following the Department of Mathematics and Statistics Policies (PDF) and other University policies listed here (PDF). More policies can be found in other university documents, especially the NAU Student Handbook (see appendices).

As per Department Policy, cell phones, MP3 players and portable electronic communication devices, including but not limited to smart phones, cameras and recording devices, must be turned off and inaccessible during in-class tests. Any violation of this policy will be treated as academic dishonesty.

Here are some important dates:

**September 5:**Labor Day (no classes)**September 8:**Last day to drop a course (without a “W”)**September 10:**Department Picnic**October 28:**Last day to withdraw from a course (with a “W”)**November 11:**Veteran’s Day (no classes)**November 24-25:**Thanksgiving Holiday (no classes)**December 12:**Final Exam (10:00AM-12:00PM)

There are many resources available to get help. First, you are allowed and encouraged to work together on homework. However, each student is expected to turn in their own work. You are strongly encouraged to ask questions in our Discord discussion group, as I (and hopefully other members of the class) will post comments there for all to benefit from. You are also encouraged to stop by during my office hours and you can always email me. I am always happy to help you. If my office hours don’t work for you, then we can probably find another time to meet. It is your responsibility to be aware of how well you understand the material. Don’t wait until it is too late if you need help. *Ask questions*!

Tell me and I forget, teach me and I may remember, involve me and I learn.

Any changes to this syllabus made during the term will be properly communicated to the class.

If you want to sharpen a sword, you have to remove a little metal.

The "Rights of the Learner" were adapted from a similar list written by Crystal Kalinec-Craig. The first paragraph of "Commitment to the Learning Community" is a modified version of statement that Spencer Bagley has in his syllabi. Lastly, I've borrowed a few phrases here and there from Bret Benesh.

Mathematics & Teaching

Northern Arizona University

Flagstaff, AZ

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MAT 226: Discrete Math

MAT 526: Combinatorics

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Flagstaff and NAU sit at the base of the San Francisco Peaks, on homelands sacred to Native Americans throughout the region. The Peaks, which includes Humphreys Peak (12,633 feet), the highest point in Arizona, have religious significance to several Native American tribes. In particular, the Peaks form the Diné (Navajo) sacred mountain of the west, called Dook'o'oosłííd, which means "the summit that never melts". The Hopi name for the Peaks is Nuva'tukya'ovi, which translates to "place-of-snow-on-the-very-top". The land in the area surrounding Flagstaff is the ancestral homeland of the Hopi, Ndee/Nnēē (Western Apache), Yavapai, A:shiwi (Zuni Pueblo), and Diné (Navajo). We honor their past, present, and future generations, who have lived here for millennia and will forever call this place home.