# FAMUS

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.

# Schedule Fall 2016

Note that talks are listed in reverse chronological order.

### The Odd Perfect Number Mystery

Date: December 9, 2016

Speaker: Jeff Rushall (NAU)

Abstract: Numbers like 6 = 1 + 2 + 3 and 28 = 1 + 2 + 4 + 7 + 14 are identical to the sums of the smaller counting numbers that divide them evenly divisors. These kinds of numbers are called PERFECT NUMBERS. They are actually very rare - there are only two other perfect numbers smaller than 10,000. And there are many easy-to-ask questions about perfect numbers, including: How many perfect numbers exist? How are perfect numbers found? Why do we care about perfect numbers? And perhaps the most important question of all: Do any ODD perfect numbers exist? [PDF of Flyer]

The faculty guest-to-be-interviewed is Sarah Watson (NAU).

### Should you consider graduate school in statistics or mathematics education or mathematics?

Date: December 2, 2016

Speaker: Derek Sonderegger (NAU)

Abstract: The presentation is being given by Dr. Derek Sonderegger, who is a member of the graduate operations committee here in our department. He will give the who/what/when/how/why of considering graduate school, applying for graduate school, and being successful in graduate school, and his comments will be directed at the graduate programs in our department. The “guests” this week will be several current and former graduate students in our department, who will present all sorts of interesting and colorful thoughts on the joys of attending graduate school in math/stat/math ed here at NAU. FREE PIZZA will be served. [PDF of Flyer]

### Are you a topological pool shark?

Date: November 18, 2016

Speaker: Kathryn Bryant (Colorado College)

Abstract: The classic game of pool/billiards is played on a table. Traditionally, pool tables are flat, tend to have six pockets, and have four bounding walls that prevent the billiard balls from escaping the table. Which of these table characteristics are topological properties? What happens to the game of pool if we change some/all of these properties? Can YOU make a shot on a torus? This talk will be an interactive exploration of the topological properties of a surface that may (or may not!) make it desirable for pool. [PDF of Flyer]

The faculty guest-to-be-interviewed is also Kathryn.

### The Shoelace Formula

Date: November 4, 2016

Speaker: Jeff Rushall (NAU)

Abstract: In this presentation, I will present a strange and yet simple formula that one can use to measure areas of polygons in the plane. This strange and yet simple formula uses just addition, subtraction and multiplication, and no calculus. It’s neat, it’s cute, and it’s fun. [PDF of Flyer]

The faculty guest-to-be-interviewed is David Deville (NAU).

### My 2015-2016 Sabbatical Year

Date: October 21, 2016

Speaker: Jeff Rushall (NAU)

Abstract: In this presentation, I will explain what a sabbatical is, why they exist, and then will tell a few math stories and several travel stories (my family and I went to Europe for the year). And yes, there will be pictures o’plenty. [PDF of Flyer]

The faculty guest-to-be-interviewed is Shannon Guerrero (NAU).

### The Shoelace Counting Problem

Date: October 14, 2016

Speaker: Jeff Rushall (NAU)

Abstract: The Shoelace Counting Problem is simple to state: how many different ways can one lace a “normal” pair of shoes (“normal” means that the shoes have laces, and eyelets, and so on). It turns out that this is kind of a tricky - and entertaining - counting problem. And it turns out that there are several different answers to the question! It also turns out that having a lot of experience tying and lacing shoes doesn’t really help answer these questions. I will bring visual aids to aid in my presentation. [PDF of Flyer]

The faculty guest-to-be-interviewed is Todd Wolford (NAU).

### Gödel’s Theorem

Date: October 7, 2016

Speaker: Ian Williams (NAU)

Abstract: A theorem so profound it forever changed the philosophy of math, Gödel’s work questions the very nature of what we can know through and about mathematics. And the implications of this result are so mesmerizing, so deep, so novel that we will condense a couple years of graduate math and philosophy into 35 minutes and only talk about the really interesting parts. Listen carefully. And as always, I will teach my secret techniques for recalling from memory the digits of $\pi$ up to any length. [PDF of Flyer]

The faculty guest-to-be-interviewed is Matt Fahy (NAU).

### The Tower of Hanoi, Part II

Date: September 30, 2016

Speaker: Jeff Rushall (NAU)

Abstract: I gave a FAMUS a few years ago on the Tower of Hanoi; this talk will be an update on the well-known puzzle (hence the “Part II” in the talk title). In addition to introducing some new variations of the puzzle, I will discuss the recently-published solution to the 4-peg puzzle. [PDF of Flyer]

The faculty guest-to-be-interviewed is Roy St. Laurent (NAU).

### Curious and Unusual Numbers

Date: September 23, 2016

Speaker: Ian Williams (NAU)

Abstract: An introduction and shallow exposition concerning the numbers I find the most fascinating, cool, strange and spooky.

The faculty guest-to-be-interviewed is Christina (NAU).

### The Tree of Pythagorean Triples

Date: September 16, 2016

Speaker: Jeff Rushall (NAU)

Abstract: A Pythagorean triple is any set of three positive integers - like (3, 4, 5) or (5, 10, 15) or (5, 12, 13) - that satisfy the Pythagorean Theorem. It has been known for a long, long time that there are infinitely many Pythagorean triples. But it’s only in the last couple of decades that mathematicians have found some clever ways of listing and organizing all of them. This talk will explain how one presents all Pythagorean triples, and will describe some related open/unsolved questions. [PDF of Flyer]

The faculty guest-to-be-interviewed is Dana Ernst (NAU).

### The Impossible Sum

Date: September 9, 2016

Speaker: Jeff Rushall (NAU)

Abstract: The talk will investigate the infinite sum $1+2+3+\cdots$ and will show why this sum exists and is important. [PDF of Flyer]

The faculty guest-to-be-interviewed is Ian Williams (NAU).