Piazza Class page.
In a few weeks, I'd like to do an exercise in hyperbolic geometry. For this, you can either download and print
some of the templates that I have on my page
Make a Hyperbolic Football!, or I can send
you some that I have printed.
The ones that I have printed are on heavy-weight paper and done on a laser printer; I have found out the hard way that this does not
work so well with lighter-weight paper.
If you want the templates that I have printed, I'll need your addresses, so that I can send them to you.
As I am in Canada, this will take 1-2 weeks, hence the reason that I am writing you now.
In short, send me your address, I'll send a large manila envelope with several printed templates and directions for making a hyperbolic football.
(Actually, you probably would call this a hyperbolic soccer ball.)
I will also be returning your papers this week with a summary of your homework grades, and a little context for these.
The papers were largely well-written, which was nice to see.
Week 9: 20 March 2017.
- Opening Remarks:
The theme this week is the the beginning of modern algebra and the role of mechnics from physics on mathematics, as an algebraist, physics
major, and now applied mathemeician, I appreciate these topics.
It starts with the revival of elementary number theory, particularly in the work of Fermat.
Then we read the story of the start of more advanced number theory in the theory of elliptic integrals and
their transformations–this is for background when we discuss complex elliptic curves.
While it is slightly out of place, we will also read the chapter on mechanics (perhaps this would have been better to do when we read about
the Calculus).
It is worth noting that in the first half of the 19th century the study of elliptic integrals and elliptic functions was one of the
main topics in mathematics.
While terminology from that time persists, this is no longer an area of current research, although it informs much of modern mathematics,
from algebraic geometry to the proof of Fermat's last Theorem (Wiles' Theorem) to the extraordinarily deep Langlands program that lies at
the interface of number theory, analysis, and representation theory.
The story of Fermat's Last Theorem was big news 20 some years ago. When Andrew Wiles announced his proof (at a conference in
Cambridge) and released a manuscript, mathematicians all over the world started to study it for Wiles was a widely-known and highly
respected mathematician—and not a crank (There is a continuous rain of papers purporting to prove famous results with elementary
means, almost all of which have easily detected flaws; These are typically sent to famous mathematicians. When I was a student at
Cambridge there was a bulletin board in the mathematics department common room devoted to letters from mathematical cranks,
and I have even received several such manuscripts and letters.)
After Wiles' announcement, some faculty at the University of Chicago set up a study group, where we read his paper and lectured on it and
the background material for most of a year; this fell apart when Wiles retracted his paper, having found an error that he later corrected
with the help of Richard Taylor.
The chapter on mechanics covers a lot of history, from the late medieval period until 1900.
This begins with relations between velocity, acceleration, and distance, and ends with chaotic motion and fluid mechanics.
- Reading:
- Chapter 11 in Stillwell's book. This covers the revival of number theory and
some great little gems, such as Fermat's little theorem (which is the basis for one of
the first public-key cryptosystems), as well as his famous Last Theorem (Section 11.3).
- Chapter 12 in Stillwell's book. Some of the topics in this book are more advanced (e.g. the transformations of elliptic
integrals and how it leads to periodic functions with two independent periods), so I'd rather have you read about this than do many
problems in this chapter.
- Chapter 13 in Stillwell's book. Pages 262–263 are a bit cumbersome, and Fulling has a succinct and easy summary
of d'Alembert's derivation of the wave equation.
- Assignment: Due Monday, 27 March 2017. (HW 10)
To hand in: Email a .pdf to both
Bennett Clayton
bgclayton@math.tamu.edu
and Frank Sottile.
fjsteachmath@gmail.com
- Exercises 11.2.1, 11.2.2, and 11.2.3 in Stillwell.
These give a refreshingly elementary proof of Fermat's Little theorem.
- Exercise 11.4.4. For this, recall the parametrization of Pythagorean triples.
Use that to deduce Fermat's last Theorem in the case of n=4.
- Exercises 13.5.1 ad 13.5.2.
- Do the steps in Fulling's explanation of d'Alembert's derivation of the wave equation.
Last modified: Sun Mar 19 20:50:30 EDT 2017