Combinatorics

Week 12 | Week 13 | Week 14

Tuesday, April 19

• Cyclotomic polynomials and Möbius inversion

Class notes

Thursday, April 21

• Graph colorings: Planarity, graph minors, the 6 and 5-color theorems for planar graphs

For graph colorings, the corresponding video lectures from last year are April 8, April 13, and April 15.

Suggested reading

• Cyclotomic polynomial (Wikipedia)
• Möbius inversion formula (Wikipedia)
• Planar graph (Wikipedia)
• Four color theorem (Wikipedia)
• Hadwiger conjecture (Wikipedia)
• Robertson–Seymour theorem (Wikipedia)