The “Friday Afternoon Mathematics Undergraduate Seminar” (FAMUS) is a weekly event consisting of announcements, talks, and faculty interviews. FAMUS takes place most Fridays at 3:00-4:00pm in Room 164 of the Adel Mathematics Building. Typically the first half of FAMUS consists of a talk on a mathematical topic while an interview of a faculty member takes place in the second half. FAMUS is hosted by Jeff Rushall.

Come join us for some entertaining talks! Refreshments always served.

Note that talks are listed in reverse chronological order.

**Date:** December 8, 2017

**Speaker:** Jeff Rushall (NAU)

**Abstract:** The title tells most of the story. This talk will present the stories of some fairly well-known mathematicians who met their demise in tragic, or bloody, or quasi-twisted ways. There seems no better way to end the semester and prep for finals than with a talk like this.

The faculty guest this week is Katie Louchart. [PDF of Flyer]

**Date:** December 1, 2017

**Speaker:** Jeff Rushall (NAU)

**Abstract:** This week’s topic is intriguing and based on the following questions:

- Is it possible to remove all points from the interval [0, 1] and have anything left?
- Is it possible to remove all points from the unit square and have anything left?
- Is it possible to remove all points from the unit cube and have anything left?

The answer to all three questions is YES. And for the record, what is left is very, very bizarre. And for the record, what is left is going to be discussed and investigated by the NAU Math Club next spring! (They are going to build a partially-constructed Menger sponge.) After the talk, there will be no faculty guest interview. Instead, we will watch 2 short and informative videos about one of the aforementioned bizarre objects. [PDF of Flyer]

**Date:** November 17, 2017

**Speaker:** Terry Blows (NAU) and a few current/former NAU grad students in Math/Stat/Math Ed

**Abstract:** The talk will focus on this question: Why should YOU consider grad school in math, statistics or math education? After the talk, PIZZA WILL BE SERVED. There is no faculty guest this week. Instead, PIZZA WILL BE SERVED. All are welcome to attend! [PDF of Flyer]

**Date:** November 3, 2017

**Speaker:** Matt Fahy (NAU)

**Abstract:** Complex numbers move around in interesting ways when subject to (even pretty simple) operations. I will use a series of visualizations to investigate the motion of sets of complex numbers under certain functions and show how such investigation can result in famously strange geometric objects.

The faculty guest this week is, not surprisingly, Matt Fahy. [PDF of Flyer]

**Date:** October 27, 2017

**Speaker:** Dana C. Ernst (NAU)

**Abstract:** In last week’s episode, we introduced the Catalan numbers and explored a few collections of objects that were counted by the Catalan numbers. In this episode, we will start by reviewing what we covered last week and then play with a few more collections of objects, each of which is counted by the Catalan numbers. Attendance at last week’s talk not required.

The faculty guest is Bahattin Yildiz, our new professor of mathematics. [PDF of Flyer]

**Date:** October 20, 2017

**Speaker:** Dana C. Ernst (NAU)

**Abstract:** In this talk, we will discuss my favorite sequence of numbers: the Catalan numbers. The Catalan numbers are a sequence of natural numbers that crop up with surprising frequency in counting problems. The first few numbers in the sequence are 1, 1, 2, 5, 14, 42, 132. After a brief history of the sequence, we will take a tour of several collections of objects, each of which is counted by the Catalan numbers. Our exploration will provide an introduction to a field of mathematics called enumerative combinatorics.

The faculty guest is Angie Hodge, our new professor of mathematics education. [PDF of Flyer]

**Date:** October 13, 2017

**Speaker:** Jeff Rushall (NAU)

**Abstract:** The Cannonball Problem is the search for the magic number of cannonballs that can be both stacked into a perfectly-shaped square pyramid AND be laid out on the ground as a perfect square. The problem goes back centuries, and the full tale includes talk of the Ancient Greeks, snowflakes and pirates.

The faculty guest is Nandor Sieben. [PDF of Flyer]

**Date:** October 6, 2017

**Speaker:** Etude Oneel-Judy (NAU undergrad)

**Abstract:** The design for a topological quantum computer is based on anyon braiding. It uses topology to protect quantum information against decoherence. We may model the space-time trajectory of a system of $n$ anyons with the $n$-strand braid group $B_n$. Storing and manipulating information in the representation spaces of $B_n$ is the foundation of Topological Quantum Computation. I developed an algorithm that allowed the classification of the unitarizable representations with dimension 5 or less for the braid group $B_5$.

The faculty guest is Ellie Kennedy. [PDF of Flyer]

**Date:** September 29, 2017

**Speaker:** Jeff Rushall (NAU)

**Abstract:** This talk will present some moments in mathematical history where some well-known mathematicians made some semi-embarrassing mistakes while trying to solve some well-known problems. It’s a bit of history, a bit of comedy, and is intended to be both fun and enlightening.

The faculty guest is Sal Vera. [PDF of Flyer]

**Date:** September 22, 2017

**Speaker:** Jeff Rushall (NAU)

**Abstract:** This talk focuses on a famous puzzle first investigated by Gauss: counting the number of integer lattice points that lie inside a circle of radius “r” centered at the origin. Much is known about this problem, but there are still some unanswered questions involving the preciseness of the formulas used for estimating the number of such points.

The faculty guest this week is Dr. Dana Ernst. [PDF of Flyer]

**Date:** September 15, 2017

**Speaker:** Jeff Rushall (NAU)

**Abstract:** I will talk explain a curious piece of mathematical history - namely, the discovery of a special set of prime numbers that are now known as Fermat primes - and what their discoverer, Pierre de Fermat, got right and what he got wrong. I will also explain why Fermat primes are still interesting today.

The faculty guest this week is Dr. Terry Crites, who is our current department chair. [PDF of Flyer]

**Date:** September 8, 2017

**Speaker:** Jeff Rushall (NAU)

**Abstract:** I will talk about the math I did, the traveling I did (to some semi-exotic places), and show you some really neat pictures (involving both math and traveling).

The faculty guest this week is Amy Rushall, who (among many other very important things) happens to be the new Academic Director of the Lumberjack Math Center. [PDF of Flyer]