# book with lot of examples on abstract algebra and topology

I have read a lot of blogs and forums to find out the best of the books on Abstract algebra and Topology but on going through the books I realized that they are full of proofs and all kind of theorems and corollaries. But the disappointing point is that there are either very small number of examples or none at all to support that particular theorem or proof. My idea of example is practically calculating using a set with contents rather than just saying "a set of integers" and the calculations should go to the end, for example calculating index in subgroups. Everything should be step by step.

I went through "Topics in Algebra" by I.N.Herstein but it's full of rigor. I faced similar problems with topology.

Please help me by suggesting books where I can find lot and lot of simple examples on these topics. Please don't suggest any advanced book but something that keeps me near the base with lot of permutations of ideas. Even if you have something to suggest other than these, you are most welcome.

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Abstract Algebra by Dummit and Foote has lots of examples –  William Aug 19 '12 at 17:40
Excellent advice from William. Dummit & Foote. –  Andrew Aug 19 '12 at 17:44
For examples in topology, try the topological picture book. –  Baby Dragon Aug 19 '12 at 18:11
When you say rigor, do you really mean the books "use symbol manipulation without much in the way of explanation, and it is hard to develop intuition from that"? That is kind of the vibe I'm getting, and I can appreciate that complaint, but I just wanted to say that rigor is a completely inappropriate word for describing that. –  rschwieb Aug 19 '12 at 21:27
$Abstract Algebra$ by W. E. Deskins. –  ᴊ ᴀ s ᴏ ɴ Aug 20 '12 at 3:33

For algebra, Dummit and Foote is as easy and gentle an introduction as you could ask for. It's not quite as easy for topology.

I happen to write a blog post that collected various answers and topology book recommendations from MSE. For ease, I've copied over the content below. But to follow any hyperlinks, which I didn't copy over (Wordpress has annoying formatting), I'd recommend just looking at the post itself of googling the corresponding term.

A MSE Collection: Topology Book References

To be clear, this is a compilation of much (not all) of the discussion in the following questions (and their answers): best book for topology? by jgg, Can anybody recommend me a topology textbook? by henryforever14, choosing a topology text by A B, Introductory book on Topology by someguy, Reference for general-topology by newbie, Learning Homology and Cohomology by Refik Marul, What is a good Algebraic topology reference text? by babgen, Learning Roadmap for Algebraic Topology by msnaber, What algebraic topology book to read after Hatcher’s? by weylishere, Best Algebraic Topology book/Alternative to Allen Hatcher free book? by simplicity, and Good book on homology by yaa09d. And I insert my own thoughts and resources, when applicable. Ultimately, this is a post aimed at people beginning to learn topology, perhaps going towards homology and cohomology (rather than towards a manifolds-type, at least for now).

One cannot mention references on topology without mentioning Munkres Topology. It is sort of ‘the book on topology,’ and thus I’ll compare all other recommendations to it. When I was blitz-preparing from my almost-no-topology-outside-of-what-I-learned-in-analysis undergraduate days to Brown’s (and the rest of the world) topology-is-everywhere days, I used Munkres. In fact, Munkres once said that he explicitly wrote his book to be an accessible topology book to undergrad. I thought it was alright, although it wasn’t until much later that I began to see why anything was done the way it was done. If the goal is to immediately go on to learn algebraic or differential topology, some think that the first three chapters of Munkres is sufficient. Munkres serves primarily to give an understanding of the mechanics of point set topology.

Willard’s General Topology is a more advanced point-set topology book. The user Mathemagician1234 says in a comment that it is practically the Bible of point-set topology, and extremely comprehensive. It has a certain advantage over Munkres in that it’s published by Dover for cheap. In a comment on a different thread, Brian M. Scott suggests that for a mathematician of sufficient maturity, Willard is superior to Munkres and Kelley’s General Topology. Sean Tilson wrote up an answer discussing Willard as well. In short, he thinks it is superior to Munkres, but that it is necessary to do the exercises to learn some key facts. In Munkres, this is not the case, but one needs to do exercises to develop any sort of intuition with Munkres.

If Willard is much harder than Munkres, it would seem that Armstrong’s Basic Topology is comparable. It’s part of the Undergraduate Texts in Math series. I know many people who learned point set from Armstrong rather than Munkres. I have personally only cursorily glanced through Armstrong, and I found it roughly comparable to Munkres. When I read the reviews on Amazon for Munkres and Armstrong, however, there is a strange discrepancy. Munkres far outscores Armstrong (whatever that really means). Perhaps this is due to the recurring theme in the top reviews of Armstrong, which say that Armstrong deviates from the logical (and some would say, intuition-less) flow of Munkres to instead ground the subject in a diverse set of subjects. On the other hand, this review says that Munkres is simply more extensive. This ultimately leads me to believe that it’s a matter of taste between the two (although Munkres is much longer). But the autodidact’s guide recommends this book as an undergraduate text.

On a different note, there is a freely read (but not printed) book by S. Morris called Topology without tears. This is a link to the pdf on his website. I should note that the version linked is not printable. There is a printable version, but you will need the author’s permission to print it. I think this book is very readable, and is perhaps the gentlest introduction text here (for better or worse).

While all the texts mentioned so far have sort of been aimed at developing the skill set necessary to learn algebraic/differential topology, there is a book Introduction to Topology and Modern Analysis by Simmons that is instead aimed at the topology most immediately relevant to analysis. It comes very highly recommended for those interested in that niche.

If, on the other hand, you are gung-ho towards algebraic topology, then Massey’sA basic course in algebraic topology has sufficient introduction to the material that it might be used as a first topology text (vastly helped by a course in analysis). But the homology theory section is… lacking.

Finally, John Stillwell wrote a book Classical Topology and Combinatorial Group Theory which has a very interesting presentation and selection of material is atypical. But it seems like a pretty interesting angle of approach.

One might consider using Singer and Thorpe’s Lecture Notes on Elementary Topology and Geometry as a supplement to one of the above texts, as it is known to give a big picture. It actually introduces point-set, algebraic, and differential topology as well as some differential geometry. But it’s very short, very terse, and it has no exercises. So it is absolutely not a replacement for learning point-set topology. One might also use Viro’s Elementary Topology (mentioned below) or Counterexamples in Topology (mentioned below) as a supplement. Counterexamples might be particularly nice, because Munkres has a tendency to give really pathological counterexamples sometimes.

It’s also good to know what books to not use as an intro text, but that might be great supplements or advanced texts. This includes:

1. Alexandroff’s Elementary Concepts of Topology: It is simply too hard.
2. Viro’s Elementary Topology, Textbook in Problems (this is a link to his website, where it’s freely available): although it would be a good supplement.
3. Seebach and Steen’s Counterexamples in Topology (a Dover book): it doesn’t serve to teach topology, but it’s full of exactly what it says – counterexamples.
4. Dugundji’s Topology or John Kelley’s General Topology: these are graduate texts, and they remind me of the difference between, say, Atiyah-Macdonald (an intro-t0-commutative-algebra text) and Matsumura or Eisenbud (more advanced texts, both more useful and much more difficult). In other words, these are good ‘next’ books on topology, but not introductions. For someone who already knows their stuff, though, these seem great.
5. Engelking’s General Topology: this is the reference on topology, but not an introduction. This is to general topology what Lang is to Algebra. It is not aimed at differential nor algebraic topology, but is instead designed to be a reference. If interested, make sure to get the 1989 second edition, which is expanded and updated.
6. Bourbaki: this is another reference, not meant for an introduction to the subject. This answer on MathOverflow has comments to it that speak of some of the unfortunate pitfalls of Bourbaki as well.
7. Spanier: It has a tremendous amount of material, but I’ve almost never heard or read any other redeeming aspect of the book. Chicago’s mathematics bibliography mentions that “… glad I have it, but most people regret ever opening it.
8. Almost any book with “Algebraic Toplogy” or “Differential Topology” in the title.

Now, away from the intro-to-general topology and instead towards intro-to-algebraic topology:

The classic choice here is now Allen Hatcher’s Algebraic Topology (this is a link to his webpage, where he has the book available for free download). Some might say that Peter May’s freely available book is the other ‘obvious’ choice. But for this, it’s easy to say that since they’re both freely available, you might just try them both until you find one that you prefer.

Hather’s book has a large emphasis on geometric intuition, and it’s fairly readable. I learned from this book, and my initial dislike (I had a hard time with some of the initial arguments) turned into a sort of respect. It’s a fine book. May’s book (called A Concise Course in Algebraic Topology) is, in May’s own admission, too tough for a first course on the subject. But it has a very nice bibliography for further reading.

Tammo Tom Dieck has a new book, Algebraic Topology, which just might be loved (even by Hatcher himself). And Rotman’s book is generally well-regarded.

Interestingly, the most common response at MSE when asked “What is the best alternative to Hatcher?” was along the lines of “No, use Hatcher. It’s lovely.”

There are also some additional free sources of notes. There are complete lecture notes of K. Wurthmuller and Gregory Naber (available at their websites and elsewhere).

I want to point out the autodidact’s guide and Chicago’s undergraduate mathematics bibliography again, because they’re good places to look in general for such things.

I learned from Herstein for algebra and Munkres for topology, and they both require you to do exercises to grasp the material. And that's how learning almost anything else in math from a text will be, so that's okay.

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thanks for sharing info !! –  Rorschach Aug 20 '12 at 6:25

I addition to William's above mentioned suggestion which is the best especially for what you are asking, I might suggest these free videos by Benedict Gross from Harvard on algebra. They are full of examples and a beautiful presentation.

http://www.extension.harvard.edu/open-learning-initiative/abstract-algebra

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thanks for information :) –  Rorschach Aug 20 '12 at 6:25
These lectures are amazing! :) –  Vikrant Desai Jun 11 at 18:53

Ronnie Brown's Topology and Groupoids is an excellent first book on algebraic topology, and introduces most of the topology you seem to be looking for. It costs 5 pounds for the e-book, which I'm sure beats all of the other non-free books out there (and only US\$32 for the physical copy). There are lots of nice exercises and examples.

Also the algebra covered therein is largely to do with groupoids, which find an immense application in all sorts of mathematics, but are rarely mentioned outside of research-level material. They are not hard to understand, and are a great way to get into algebraic topology.

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+1 for an excellent and unorthodox topology book-but it has one drawback, it doesn't discuss homology theory. It intentionally does this because it's trying to develop as much of modern topology as possible using only groupoids and homotopy theory. If you use this-and I strongly suggest you do-you'll have to supplement it with a "standard" text like Rotman or Vick. –  Mathemagician1234 Dec 5 '12 at 20:59

I also learned algebra from Herstein's Topics In Algebra and I still find it a wonderful book that really tests the mettle of a mathematics major with its exercises. If you need a more concrete approach with more specific examples, I can't give a better recommendation then E.B. Vinberg's A Course In Algebra. The book is at a comparable level to Herstien, but it has a much more geometric bent and has literally thousands of terrific and concrete examples-most of them drawn from not only geometry, but physics(!). It has very quickly become my favorite single reference for algebra and I think it might be just what you're looking for.

For topology, the situation's a little tricker. I also learned topology from Munkres-which I think does have quite a few examples that are well chosen. But I don't think I can improve on mixedmath's response-he gives you pretty much all the well-known references,along with evaluations I more or less agree with. I particularly agree with his recommendations of Engelking (almost impossible to get in the U.S. and ridiculously expensive,but if you're serious about general topology, it's a must-have), Singer/Thorpe (very classical, but extremely broad coverage and gives terrific insights for the beginner) and Armstrong (beautifully written and covers all the essentials).

There are 2 other books I'd like to add and recommend if you're up to them-Victor Prasolov's Elements of Combinatorial And Differential Topology and Elements of Homology Theory. Both are available through the AMS. Together,they give the broadest and most complete coverage of topology I've ever seen-with lots of examples and exercises and all from a very visual and geometric point of view. But they aren't easy books and you'll really have to have your chops on for them.

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Someone upvoted this,then someone else downvoted it.My fan club at work again. –  Mathemagician1234 Aug 20 '12 at 1:34
There's a pleasant completion in this. I explicitly mention you in my blog post, you mention my blog post mentioning you in your answer, and now I mention that you mentioned my... (etc.)... A pleasant completion. –  mixedmath Aug 20 '12 at 1:44
@Mathemagician1234: thanks for such nice help :) –  Rorschach Aug 20 '12 at 6:28
Prasolov's book, from what I read of it, is not a great "beginner-friendly" book with lots of examples --- I don't think OP would have a fun time with it, given what the OP has told us. Similarly, Elements of Homology Theory is a pretty heavy text. I do agree that Armstrong is a great text for beginners, though; I even found a few fun problems that I hadn't seen before in it. –  james Aug 22 '12 at 2:05
@Mathemagician1234 Also, just out of curiosity, and not to start a row, but every post I see of you has recommendations from a number of books from a number of diverse subjects --- have you worked through all of the books you recommend? Or just hear about them second-hand? Either is fine; again, just curious. –  james Aug 22 '12 at 2:06

And then there is Counterexamples in Topology, which is really just a massive book of examples of various spaces that show which properties of topological spaces imply other properties, or fail to. If you are looking towards algebraic topology you probably won't use these spaces, but it is good to know they exist (for instance, I needed to remember that a compact space may not necessarily be locally compact, so I pulled out my copy).

The necessary definitions to (with effort!) understand the examples are included.

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Dummit and Foote is good for basic finite group theory, which makes sense as the book was written at a time when the classification of finite simple groups was THE big deal in algebra.

That said, I feel like group theory is a lot easier to understand if it's paired with some representation theory from the beginning, and Dummit and Foote doesn't really do much in that regard; as I recall, they only talk about characters (in the sense of one-dimensional representations), and that's relegated to an appendix.

And the section on ring theory seems like more of a forced march through an ever-increasing forest of definitions. I feel like Aluffi's Algebra: Chapter Zero is an easier read where rings are concerned.

The beginning of Fulton and Harris's Representation Theory, which deals with representations of finite groups, is a good supplement to beginning group theory.

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