### Solutions and Elaborations for Weibel's "Introduction to homological algebra"

While reading the book, I attempted to fill in details in proofs, perform checks, correct errors, and do exercises in the following notes. I hope they can be helpful. There are only solutions for parts of chapters 3, 4, and 8. Feel free to contact me with any corrections. Last updated 1/19/17. Link

The errata, available here, are helpful as well: Link

### Injective Modules are Algebraically Closed

A slightly more concrete statement of what an injective module is.

Link### Introductory Category Theory Notes

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

Day 1Day 2

Day 3

### Intro to Sheaves and Abelian Categories

Notes for a 2 hour talk introducing sheaves and abelian categories. Aimed at graduate students who have completed a graduate course or two in algebra and topology.

Link### Solutions to Recurrence Relations:

These notes derive the fundamental solutions associated to linear homogeneous recurrence relations using linear algebra, including the repeated eigenvalue case. The approach in these notes differs from the usual approach in that I do not use generating functions.

Link