Errata for 'Algebra - Notes from the Underground' (2021)

Highlighted in red are the needed changes, embedded in text matching the published version and identified by page and position on the page (e.g., `p.10, top'). A bold reference indicates an error in the published version which may be more confusing, such as a missing hypothesis in an exercise.

This list is bound to grow forever. (28 items so far.) The contribution of many readers is gratefully acknowledged.

Last updated: 4/13/22.


  • Chapter 1


  • Chapter 2


  • Chapter 3


  • Chapter 4


  • Chapter 5


  • Chapter 6


  • Chapter 7


  • Chapter 9


  • Appendix A


  • Appendix B