Solutions and Elaborations for Weibel's "Homological Algebra"


Some notes I wrote in grad school while working through the text. I recommend only using them if you're really stuck: there may be errors, and writing solutions tends to be more educational than reading them. Last updated 1/19/17.

Injective Modules are Algebraically Closed


Injective modules are important critters in homological algebra with an (in my view) un-intuitive definition. These are notes about a slightly more concrete take on what it means to be an injective module.

Solutions to recurrence relations


An approach to solving recurrence relations via linear algebra.

Introduction to categories

Lecture 1

Lecture 2

Lecture 3

Notes from a series of lectures on category theory for first-year graduate students.

Sheaves and abelian categories


Notes from an introductory talk on sheaves and abelian categories