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

The syllabus is posted here.

Bonus lectures continued on Thursdays at the usual time, beginning on 3/18 and ending on 7/15.

The most up-to-date lecture notes will always be posted here.
update (3/2023): I will be teaching the same course in spring 2023. I'll be reusing and polishing the notes, after which they'll be published by Cambridge University Press in their Studies in Advanced Mathematics series. So, the version linked here will no longer change, while a mildly tweaked version will slowly appear here.
update (12/2023): Please see here for the most up-to-date information on the book.

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, 4/15, 4/22, 4/29, 5/6, 5/20, 5/27, 6/10, 6/17, 6/24, 7/8.