In 2018 spring, I taught Math 422 “Introduction to Geometric Topology” at POSTECH. The main purpose of this course was to introduce algebraic and differentiable approaches to geometric topology, as a second course in topology for undergraduate students. Several colleagues of mine ask whether the lecture notes I provided to my students are still available, so I keep links below.

- #1 Homotopy and fundamental group
- #2 Change of basepoint and free homotopy of maps $S^1\to X$
- #3 Induced homomorphisms and products
- #4 Covering spaces and graphs
- #5 Fundamental theorems on covering spaces, part I
- #6 Fundamental theorems on covering spaces, part II
- #7 Free groups and group presentations
- #8 Seifert van-Kampen theorem
- #9 Surfaces and abelianization
- #10 Knots
- #11 Wirtinger presentation
- #12 Alexander polynomial
- #13 Smooth manifolds
- #14 Regular values and fundamental theorem of algebra
- #15 Manifolds with boundary and Brouwer’s fixed point theorem
- #16 Orientation and degree