These notes were published for many years by Henry Helson, now deceased. How they will be published in the future is at the moment uncertain, but (softcover, printed, bound) copies of the current version can be obtained from me, , either for $30 by mail, or for $25 at my office, 865 Evans Hall.
They can also be printed or viewed from the files below, but the text-formatting program with which I created and maintain them is an old fashioned one that was in common use before TeX, and has shown some incompatibilities with modern printers and display tools. If you want to print out these files, start with one of them, and see how it looks. If there are problems, let me know. (The "alt_pdf" file for Chapter 7 is better in its handling of arrows than the "pdf" version on some printers, worse on others. You might compare the two.)
Note also that when a chapter begins on an
even-numbered page, the file below begins with a blank page,
for convenience in 2-sided printing.
So if you display a file and see a blank page, just page
forward to see the text.
I have put online a few corrections and changes to this version of these notes.
Table of contents, + Ch. 0, About the course, and these notes, + Ch. 1, Making some things precise. ps pdf
Chapter 2, Free groups. ps pdf
Chapter 3, A Cook's tour of other universal constructions. ps pdf
Chapter 4, Ordered sets, induction, and the Axiom of Choice. ps pdf
Chapter 5, Lattices, closure operators, and Galois connections. ps pdf
Chapter 6, Categories and functors. ps pdf
Chapter 7, Universal constructions in category-theoretic terms. ps pdf alt_pdf
Chapter 8, Varieties of algebras. ps pdf
Chapter 9, Algebra and coalgebra objects in categories, and functors having adjoints. ps pdf
References. ps pdf. Word Index. ps pdf. Symbol Index. ps pdf. Index of Exercises. ps pdf.
Answers to some students' questions from Math 245A, Spring 2008, and Fall 2011, taught from the above text.