This tag is for questions that are asking for online resources in mathematics (references, dictionaries, encyclopaedic collections, online tools, videos an lectures, etc), or asking about the mathematics behind tools and technology found on the internet.

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27
votes
10answers
2k views

Online resources for learning Mathematics

Not sure if this is the place for it, but there are similar posts for podcasts and blogs, so I'll post this one. I'd be interested in seeing a list of online resources for mathematics learning. As ...
15
votes
1answer
1k views

Overview of basic results on cardinal arithmetic

Are there some good overviews of basic formulas about addition, multiplication and exponentiation of cardinals (preferably available online)?
12
votes
1answer
1k views

Overview of basic facts about Cauchy functional equation

The Cauchy functional equation asks about functions $f \colon \mathbb R \to \mathbb R$ such that $$f(x+y)=f(x)+f(y).$$ It is a very well-known functional equation, which appears in various areas of ...
10
votes
4answers
1k views

Overview of basic results about images and preimages

Are there some good overviews of basic facts about images and inverse images of sets under functions?
6
votes
1answer
285 views

Known bounds and values for Ramsey Numbers

Is there a good online reference that lists known bounds on Ramsey numbers (and is relatively up to date)? The wikipedia page only has numbers for $R_2(n,m)$. I am specifically interested in known ...
87
votes
9answers
6k views

Are mathematical articles on Wikipedia reliable?

I know that Wikipedia gets a bad rap, and it seems like some teachers of mine have nothing better to do in class than harp on about the Great Academic Pastime of calling Wikipedia untrustworthy, but ...
23
votes
5answers
3k views

Chatting about mathematics (with real-time LaTeX rendering)

Do you know about some tools which can be used for online chat about mathematics? In particular, I am interested in software which would be able to render LaTeX formulas. (Since LaTeX is probably the ...
10
votes
5answers
5k views

Resources/Books for Discrete Mathematics

I am going to a Computer Science Course in University next year. I heard that Discrete Mathematics is whats required for Comp Sci so, I am looking for resources/books that I can read to get started ...
34
votes
7answers
26k views

Online tool for making graphs (vertices and edges)?

Anyone know of an online tool available for making graphs (as in graph theory - consisting of edges and vertices)? I have about 36 vertices and even more edges that I wish to draw. (why do I have so ...
36
votes
2answers
712 views

How do I find partners for study?

I want to find partners to study some post-graduate topics together online (because I'm pretty much out of steam as far as self-study goes, and I have problems finding a decent grad school). Are there ...
2
votes
1answer
136 views

Steiner symmetrization preserves area?

I just finished reading (and understanding) Steiner's proof of the isoperimetric inequality. His proof (which is sadly incomplete) seems to rely much on the fact Steiner symmetrization preserves area ...
125
votes
6answers
4k views

Best Sets of Lecture Notes and Articles

Let me start by apologizing if there is another thread on math.se that subsumes this. I was updating my answer to the question here during which I made the claim that "I spend a lot of time sifting ...
75
votes
23answers
11k views

List of Interesting Math Blogs

I have the one or other interesting Math blog in my feedreader that I follow. It would be interesting to compile a list of Math blogs that are interesting to read, and do not require research-level ...
35
votes
13answers
2k views

Is there a good “bridge” between high school math and the more advanced topics?

I love math and would like to know more of it. However, whenever I try to pick up a book on what I consider to be "advanced" mathematical topics, I often have a hard time understanding some of the ...
36
votes
9answers
7k views

List of interesting math podcasts?

mathfactor is one I listen to. Does anyone else have a recommendation?
8
votes
3answers
825 views

Free Graph Theory Resources

What freely available graph theory resources are there on the web? In particular, I am interested in books and lecture notes containing topics such as trees, connectivity, planar graphs, the ...
13
votes
4answers
3k views

Generating functions for combinatorics

I have no formal education in generating functions, but, based on another question, I have seen that they can be powerful for combinatorics. Are there a few general principles for using generating ...
15
votes
5answers
2k views

What does Khan Academy have to offer? Depth? Rigor?

Khan Academy - http://www.khanacademy.org/ - is often cited as a great online resource for learning mathematics and other subjects. I have heard many good things about this website and was wondering ...
7
votes
2answers
302 views

How to write special set notation by hand?

Does anyone know a good resource (preferably pictures) that illustrates a conventional way to write the special sets symbols, i.e. $\mathbb{N,Z,Q,R,C}$ etc., by hand?
0
votes
1answer
786 views

Subtraction of numbers with arbitrary bases [duplicate]

Possible Duplicate: How to do +, -, *, / with number in a base b? I am reading research papers in the category of recreational mathematics on the topic of numbers similar to Kaprekar ...
17
votes
6answers
2k views

How to go from beginner to expert in mathematics?

I'm particularly interested in knowing the order of subjects one should study to become good in mathematics. In my not so great knowledge of the subject I would say that the best place to start could ...
25
votes
1answer
395 views

How to search the internet for strings that consist mostly of math notation?

Is there a trick to search the internet for math notation? For example what if I want to search the internet for "X / ~" ? The default google search is useless for this and for similar searches ...
10
votes
7answers
10k views

Are there any good Discrete Mathematics video online?

I want to learn discrete mathematics by reading book by myself but I find sometime it's very hard to understand what author trying to say. I want to know, are there any good online video that teach ...
13
votes
4answers
736 views

Introduction to Filters in Topology

Question: What are some good resources for a student who has taken algebraic and point-set topology and who wishes to learn how filters and ultrafilters are applied in topology? Motivation: I've seen ...
6
votes
1answer
127 views

Which textbook of differential geometry will introduce conformal transformation?

Which textbook of differerntial geometry will have these formulas about conformal transformation? $$\tilde g_{ij} = e^{2\varphi}g_{ij}$$ $$\tilde \Gamma^k{}_{ij} = \Gamma^k{}_{ij}+ ...
1
vote
4answers
334 views

Which discussion board is good for homework questions?

I'm a CompSci university student and i want some help for my math questions. Therefore i am looking for a good discussion board for math homework questions. I don't know any (good), because I come ...
3
votes
1answer
103 views

Is there a 'Mathematics wiki' analogous to 'String theory wiki'?

I came across this site and am wondering if there is a similar page for Mathematics or its sub-areas. Would be very nice if there is one such site which provides 'canonical' references for each sub ...
3
votes
1answer
905 views

Differential Geometry Video Lectures

I know there's a similar question here, however since what I found there wasn't what I was looking for I thought on creating a new question. I'm studying Differential Geometry through Spivak's book "A ...
3
votes
2answers
211 views

Can anybody recommend a website or other type of resource which contains real Analysis-type questions and their solutions?

In a recent post I asked about an epsilon delta proof for an Analysis question. Before posting it I searched for similar questions and their proofs on google but all I found were computational style ...
5
votes
3answers
625 views

Infinite Series Manipulations

Is there any comprehensive list (books, online, ...) of rules for manipulating infinite series (partial sums) to find convergence of a sum? Often authors use some "trick" to compute an infinite ...
3
votes
1answer
784 views

Formula for the $n$th prime number: discovered? [closed]

I happened to stumble upon this page. Does anyone know about the validity of this claim?
2
votes
2answers
292 views

Statistics resources with examples for a C.S. student

I'm a computer science student and is fairly familiar with basic probability (calculating the probability of a event occurring, pmfs and pdfs) but I find it very difficult to grasp the concepts of ...
0
votes
1answer
131 views

A matrix has a real logarithm if it has a positive spectrum.

The title is a proposition I read in my notes that's left with no proof. Where can I read one?