**Topics from today's class**:

- The genus of a knot
- Crossing number vs. genus
- Different Seifert surfaces for the same knot
- Seifert surfaces for alternating knots
- The genus is additive with respect to connected sums

**Homework**:

- 4.22, 4.24, 4.27
- Pet knot: sketch a Seifert surface for your knot, then compute the genus (do this on paper)

**Read for next class**:

- 5.1

**Announcements**:

- There will be two cars leaving for the conference on Saturday, one at 8:15 and one at 10:15. Passengers should meet in the front of Tome. Don't forget to get a grab-n-go lunch in the morning.