TITLE: Prerequisites for Atiyah Macdonald
QUESTION [18 upvotes]: I am currently doing a one semester course on groups and rings where we have learned about (so far):
Definitions of groups, subgroups, cyclic and normal subgroups, the symmetric group, homomorphisms, isomorphisms, The Correspondence Theorem,  Product and Quotient Groups. As of yesterday's lecture we learned about the First Isomorphism Theorem and a little bit about rings.
By the end of the course we should have done rings, endomorphisms, The Orbit-Stabilizer Theorem and subjects which I am not sure about.
I am wondering if this would be sufficient to start Atiyah Macdonald; I have opened the first few pages and it looks hard. For those who have done it, what do you think are the prerequisites before doing this? Perhaps something like Herstein's Topics in Algebra?
Thanks.

REPLY [15 votes]: Algebra Prerequisites: A knowledge of the following results:

(1) The definition of ring, subring, ideal and quotient ring.
(2) The correspondence theorem in ring theory.
(3) The notion of a prime ideal, of a maximal ideal, and the facts
  that an ideal $I$ of a commutative ring $A$ is prime (resp. maximal)
  if and only if $R/I$ is an integral domain (resp. field).

In short, the first 4 pages of Atiyah and Macdonald should be in the nature of a review for you.

(4) An extensive knowledge of field theory and Galois theory; for
  example, in addition to the elements of Galois theory, you should
  probably be familiar with separable and inseparable extensions and
  transcendental extensions. (Chapter 5 on integral extensions of
  commutative rings is better appreciated if you have already studied
  the theory of algebraic extensions of fields. Transcendental
  extensions are discussed in the chapter on dimension theory. Finally, at least one result in chapter 9 (on Dedekind domains) and a few exercises in chapter 5 require a knowledge of separable and inseparable extensions in field theory.)
(5) I think the Jordan-Hölder theorem in group theory is alluded to at some point in the text. (The discussion of modules of finite length in chapter 6.)

Topology Prerequisites: A knowledge of the following results:

(1) The definition of a topological space, of open and closed sets, of
  a basis for a topology, of compact sets and Hausdorff spaces, of
  subspaces, and of continuous functions. (In the text itself, point-set
  topology is most prominent in the chapter on completions but you will
  need point-set topology for the exercises as well.)
(2) Urysohn's lemma is needed to solve exercise 4 in chapter 4 and at
  least one exercise in chapter 1 (on the characterization of the
  maximal spectrum of a commutative ring).

Summary: The most important prerequisites are point-set topology and the theory of fields. You can read chapters 1-4 of Atiyah and Macdonald with only (1)-(3) of the Algebra Prerequisites above and chapter 5 of Atiyah and Macdonald with a knowledge of algebraic and separable extensions of fields. Chapter 9 of Atiyah and Macdonald also requires a knowledge of separable extensions of fields and chapter 10 of Atiyah and Macdonald requires a knowledge of (1) of the Topology Prerequisites above.
However, in order to do the exercises in Atiyah and Macdonald (which are the most important part of the text, in my opinion), you will need all the prerequisites above. Point-set topology is an essential prerequisite in the exercises because many exercises discuss affine schemes. Also, the elements of Galois theory are needed in some exercises in chapter 5, for example.
I hope this helps!