Project III 23-24


The Poincare Conjecture

Andrew Lobb

Description

Proving the Poincare conjecture was worth $1 million and a Fields medal to a man who turned down both.

The Poincare conjecture roughly states that if you have a 3-dimensional space M in which every loop can be shrunk to a point, then M must be a 3-sphere. But what is meant here by a 3-dimensional space? Are there in fact any 3-dimensional spaces in which you cannot shrink all loops to a point? Why should we anticipate that the conjecture is true?

In contrast to 2-dimensional spaces, 3-dimensional spaces can differ amongst each other in subtle ways. We will take the Poincare conjecture as a motivation to try to understand, describe, distinguish, and catalogue 3-dimensional spaces using various techniques. Our methods will most often be highly visual - cutting up and gluing together pieces that we understand to make new spaces with interesting properties.

Prerequisites

Geometric Topology II.

Co-requisites

Topology III.

Resources

You can look up the wikipedia articles on Dehn surgery and Heegaard splitting to get some idea of the techniques used in constructing 3-dimensional spaces.

Relevant books include the following:

  • 3-manifolds, Hempel
  • Allen Hatcher's proto-book, available as online notes, is a little too advanced for this project, but it contains some nice descriptions.

email: Andrew Lobb