Math 103.  Spring 2003.   Infinity and the imagination.

 

INSTRUCTOR:  Dr.  Avery Solomon        Office: Malott 210.            

e-mail:   aps5            (dec-jan averysolomon@hotmail.com)

 

                   

DESCRIPTION

In this course, students will explore different mathematical meanings of infinity, including: infinite extent, infinitesimal, orders of infinity, potentially infinite processes, and paradoxes. We will roughly follow a sequence of  five historical periods, putting our explorations in a context of ancient and modern mathematics, science, nature, art, and philosophy.  The course will take into account different approaches to learning, and use rational investigation, imagination, discussion and writing.  Part of the course will be spent in the computer lab exploring iterations of simple arithmetic and geometric processes which are at the heart of dynamical systems and fractals. 

 

The goal of this course is for students to experience and enjoy some exciting mathematics, and to reflect on what it means to think about infinity, an important aspect of thinking mathematically.  Students should come away from the course with a greater understanding of the power of mathematics in helping us think about infinity, an experience of the deep connections between the physical world and the imagination, and a deeper appreciation of the mystery of the universe and the human mind. 

 

RESPONSIBILITIES

Class attendance and participation is required. 

Writing will be an essential part of the course. There will be a written assignment each week, to be handed in Tuesday of the next week. Homework will constitute about 60% of the grade.

There will be computer and other explorations to be completed together with a partner, which will constitute about 15% of the grade.

A final presentation/project to be done with your partner will constitute about 15% of the grade.

There will be no exams or final, but occasional quizes may constitute about 10% of the grade.

 

WRITTEN ASSIGNMENTS:

Please turn in whatever your thinking is on a question even if only to say: "I don't understand such and such" or "I'm stuck here".  Turning in homework every week, even if incomplete, will entitle you to revisit and revise the problems.  Your papers with comments will be returned.  Respond to comments, use them as invitations to explore, or clarify your understanding.  Keep responding (in writing or during office hours) to comments until you understand and have completed the question.   Also, ask questions in class, or after class, on your paper or in office hours. 

 

When I ask you to "show" that something is true, what this means is to "give an argument that a reasonable skeptic can understand and accept".  A two column proof is not required, but reasoned explanations are.  An argument can include models, pictures and examples .

 

Share your ideas with others and listen to their ideas in and out of class.  If you work something out with others, that is fine, but make sure that you understand it in your own way, that you communicate in writing your own words, and please write down your collaborator's name on your paper. You may use ideas you see in class, even to respond to a question after it has been discussed in class. Acknowledge the class' contribution to your thinking.

 

Text:

A Cultural History of Infinity    Maor, Eli.    

 

SUPPLEMENTAL MATERIAL

 

 

        Recommended also:

Images of Infinity  Hemmings, Ray and Tahta, Dick  Tarquin. 1995

Infinity and the Mind.  Rucker, Rudy. Bantam.  1983. 

 

 

OUTLINE

 

Organizing Outline: Five Historical Contexts:

 

A. 6th-3rd century BC: Early origins of thought about infinity in traditional cultures in India, Egypt, Babylonia, China. Focus on Greek  paradoxes of infinity.

B. 1st-11th century:  Hindu, Muslim, Taosit, and Buddhist views of Infinity, related to 0, equations, I-ching, and tiling.  

C. 17th-18th century: Perspective, Infinite series, calculus and perspective.

D.  19th-20th century:  Mathematical Logic and the infinite.

E.  Late 20th-21st century: Fractal Geometry and dynamical systems. 

 

Approximate Timeline of Topics

 

Ancient questions of  space, time and causality  (Two weeks:  1-2)

Cosmology: Infinite Space?  Rotating.  First Cause

Matter: Smallest particle?

Motion: Zeno

Causality: Evolution: beginningless?  Combined dependent origination

Greek:

Euclid: # of primes is infinite

Eudoxus: method of exhaustion

Eratosthenes

Archimedes: Sand reconer, Value of pi, Area of Circle, Axiom of Archimedes

Pythagoras: incommensurability Infinity and the irrational: incommensurability, square and pentagon, Pi, infinite lattice, square circle.

Square the circle, duplicate the cube

 

Causality and Infinity  (one week:  3)

Problem of infinite regress and first cause: Aristotle, Augustine and Aquinas

Self referential paradoxes: liar paradoxes.

Self-similar infinity: Land of Lakes

Theology:  Plotinus, Plato. 

India:  Infinite from the infinite yields the infinite:  Shankara articles unfolding One, Infinitesimal

China: Hwa-Yen Buddhism

Infinity and 0

Cipher for 0 or sunya around 1000 years ago.

 

Infinity and uncertainty:   (1/2 week: 4)

Paradoxes of probablity: coin toss and likelihood

Geometric probability and the dart board.

 

 

 

 Infinite sequences and Limits.  (1.5  weeks:  4-5)

Sequences and series: geometric and harmonic and Fibonacci

Spirals

Potentially infinite, limit, process.

Limits and converging:  geometric ½ + Ό + 1/8 …

Do other sequences:  2/3, 4/3, 4/5, 6/5, …

Do Harmonic series: why diverge?  And how slowly.  Oresme proved: 1250.  In appendix.

Gregory:  pi/4 = 1/1-1/3+ 1/5 –1/7 …  

Wallis:   pi/2 = 2/1 x 2/3 x 4/3 x 4/5 x …

 

Infinity and Geometry in the Renaissance and Art  (1 week 6)

Parallel

Perspective

Escher

Tiling.

 

Logic of infinity  (1.5 weeks: 7-8)

Infinity and the Real Numbers

Cantor: “all” the numbers, orders of infinity,

Paradoxes of infinity and sets.  Infinite Hotel.

Russel: definition is crucial: set with just as many members as itself.  Give self-similarity example.  Ordinal and Cardinal.

The continuum and ideas of continuity

Many and One

One to one relations and diagonal arguments.

Independence of the CH: correspondence and consistency,

Cantor: order of 2Aleph > Aleph (proof in Maor)

Platonic view, Kantian, positivist.

 

Fractals  (two and 1/2 weeks: 8-10)

Self-similarity:  land of lakes, tankhas, rucker, cantor dust

Not smooth: coastline, modeling the coast,

Fractional dimension: Why is an ant small? what has dimension 1.5

Attempt to measure smaller by larger (0), or larger by smaller (infinity)

Building fractals: Koch and Frame.

Multiple copy machines: Fern and spiral, numerical descriptions of transformations.

Genetics.  

 

Dynamical systems: exploration of iteration  (two weeks:  11-12)

Numerical iteration: multiplying and adding

Discrete dynamical systems:  quadratic or complex?

 

 

Student presentations:  (2 weeks 13-14)