This is the webpage for my winter 2021 section of Math 128 (homological algebra).

The syllabus is posted here.

Bonus lectures will continue on **Thursdays only** at the usual time, beginning on Thursday 3/18.

The most up-to-date lecture notes will always be posted here.

As explained in the lecture notes, modifications are temporarily color-coded so that they are easy to spot. In case you fall behind, it may therefore be helpful to look back through the older lecture notes, which are posted here: 1/5, 1/7, 1/12, 1/14, 1/19, 1/21, 1/26, 1/28, 2/2, 2/4, 2/9, 2/11, 2/16, 2/18, 2/23, 2/25, 3/2, 3/4, 3/9, 3/18, 3/25, 4/1.