Piazza Class page.
Week Ω: 23 April 2024.
- Opening Remarks:
This is our last week.
Your term paper is due next week.
The development of set theory, especially Cantor's revolutionary ideas, led us to finally develop a theory of infinity as a quantity, a notion that
vexed the Greeks.
The roots of this were mathematicians trying to understand the very strange sets that came up in understanding aspects of the convergence of Fourier
series (another topic mentioned only in passing that led to great mathematical developments in analysis, number theory, and combinatorics–look
up the work of Tim Gowers who was a fellow student at Cambridge when I was there).
In fact, some have said that Cantor developed the first new branch of mathematics since antiquity;
Algebra is as old as counting, and came into its own certainly in China, India, and the Islamic world.
Geometry was developed to a high degree by the Greeks,
and Analysis, while it was an outgrowth of the Calculus, can be said to have its origins at least in the amazing approximations of Archimedes.
Cantor's theory of infinite sets is also remarkably accessible; my high school calculus teacher presented to us the Cantor `middle third' set,
as well as his diagonal proof that there are more real numbers than integers–this is a topic I enjoy presenting when I talk to
highschool students and in-service teachers.
I aso had about 8-10 graduate courses on set theory, logic, and foundations, so I have a soft spot for this.
Let me add a bit to the ideas presented in Chapter 24.
Some of the results, Gödel's incompleteness theorem, the independence of the continuum hypothesis, and the negative solution to the halting
problem, are of similar nature in that science has proven that there are limits to our knowledge–some things are not knowable.
They have a similar feel to Heisenberg's uncertainty principle.
The chapter ends on some heady ideas.
You might find the following interesting:
A brief introduction to ordinal numbers and its successor
Part 2.
Lastly, you will read about combinatorics, which is the study of counting or of discrete mathematical structures.
While often derided as a mile wide and an inch deep, this mathemartical area has come into its own in the past 100 years,
and is increasingly important.
Many people argue that it should be taught instead of Calculus (a few years ago, a friend from graduate school who gave a distingushed
lecture at Texas A&M, made this point in a talk she gave–this is Kristin Lauter, who is a director of research at META)
I also work in combinatorics, among other mathematical topics, so again I have a soft spot for it.
Lest you think that my prejudices are guiding the last few weeks, I am also a huge fan of algebraic number theory, even though I do not
work in it.
- This week, you will make your four-dimensional cubes with the zometools and do the combinatorial exercise on cubes.
- Reading:
- Chapters 24 and 25 of Stillwell.
- Do: Build your four-cube.
Here are some instructions.
The cubes worksheet
- Assignment: Due Monday, 2 May 2022. (HW 14)
Here is a .pdf and a LaTeX source of the assignment.
To hand in: We are using Gradescope for homework submission.
- In Chapter 24, do the exercises 24.2.1 and 24.2.2.
- In Chapter 25, do the exercises 25.5.2, 25.5.4, and 25.5.5
- Cubes worksheet and a paragraph about your experience on the project.
Last modified: Mon Apr 22 13:32:33 PDT 2024 by sottile