David Stanovský    //   

ALGEBRAIC INVARIANTS IN KNOT THEORY 2021/22

Syllabus:

  • Fundamental concepts of knot theory - equivalence of knots, knot notation, Reidemeister moves
  • Basic knot invariants, knot coloring
  • Seifert surfaces, Seifert matrix, Alexander polynomial
  • Braids
  • Skein relations and Jones polynomial
  • maybe some applications

The fundamental material is the book Knot Theory and Its Applications by Kunio Murasugi, chapters 1-7 and 10-11, possibly a little bit from 12-14. After chapter 4, I will make a short intermezzo on knot coloring, which is the topic of my research.

As a supplementary material, videos from 2021 are available at the older website of the course. This year, we will cover similar, but not exactly the same topics.

Preliminary plan:

topic Murasugi other materials
18.2.Introduction: a computational view of knot theory.
Fundamental concepts: knots, links, knot equivalence, connected sum and prime decomposition of knots.
1.1-1.5 intro slides, full intro
25.2.Diagrams, knot tables, knot graphs. 2.1-2.3
4.3.Fundamental problems of knot theory. Some naive invariants. 3.1-3.2, 4.2-4.4
11.3.Reidemester theorem. Linking number. 4.1, 4.5
18.3.Knot coloring. 4.6, -- more on quandle coloring
25.3.Quandle coloring. Seifert surfaces and their genus. --, 5.1, 5.2
1.4.Seifert matrices. 5.2, 5.3
8.4.Equivalence of Seifert matrices. Alexander polynomial. 5.4, 6.1, 6.2
22.4.Properties of the Alexander polynomial, the signature of knot. Torus knots (construction). 6.3, 6.4, 7.1 read 7.2-7.5
29.4.Jones polynomial: definition, calculation. 11.1, 11.2
6.5.Jones polynomial: properties, generalizations. 11.3, 11.4
13.5. or 27.5.Braid group, constructing knots from braids. 10.1-10.4
20.5.Applications or Vassiliev invariants. 12-14

Other literature:

  • any book on knot theory, a particularly good one is, for instance, P. Cromwell: Knots and Links, or C. Adams: The Knot Book
  • knot coloring - Nelson, Elhamdadi: Quandles: An Introduction to the Algebra of Knots

Exam: The exam is oral. You wil be given two questions:
1) A long one, asking to explain certain topic. Example: "Define the Alexander polynomial using Seifert matrices, explain why it is an invariant and show that it is symmetric for knots." Example: "Explain the Reidemester theorem and prove it."
2) A short one, asking to calculate certain invariant. Example: "Find 5-coloring of a given knot (concrete picture will be given)."
I expect you to know all proofs and methods as explained at the lecture. In particular, if the proof was just a sketch, you are expected to understand the idea, but I will not ask more details than presented at the lecture.
There are no fixed dates for the exam. Suggest a date, I will tell you if I am available - at least a couple days ahead of your planned exam. I am in Prague most of the time, but I am not always free - I have large scale exams on general algebra, occassional meetings, etc.
Following a tradition, there is one exam date in SIS, and it is special: exam in nature (zkouška v přírodě). See SIS for a description and feel free to ask for more info.