Quote:
Originally Posted by oranges
Algebraic topology, eh? I guess it's going to be quite interesting to take this course and 3T03 concurrently. But anyway, thanks for the suggestion.
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Well, at least from what I've seen of knot theory, its ideas are motivated by those of algebraic topology. You find particular algebraic properties which are invariant under "tying". For instance, two knots with equivalent diagrams can be related by 3 tying moves (
Reidemeister moves).
What are some examples of invariants?
1. Tricolourability -- how you do this is explained better by a
picture than words:
In particular, note that this distinguishes any nontrivial knot (i.e. knot which cannot be deformed to the unknot, or circle), from the unknot.
2. Knot polynomials. Here's the simplest
example.