## Mathematical Links

I created and maintain the

Erdős Problems collection, a living repository of the problems (and solutions thereof) posed by

Paul Erdős.

For the cutting edge in mathematical research, keep an eye on the

arXiv (

number theory and

combinatorics are my usual haunts).

For any research-level question or procrastination, you can't do better than

Math Overflow.

Any lower level mathematical questions belong at

Math StackExchange.

For looking up definitions and background

Wikipedia,

Encyclopedia of Mathematics, and

Mathworld are all good sources.

Scholarpedia also has excellent survey articles on some topics.

If, like me, you shy away from learning how to use mathematical software and prefer the internet to do it for you,

Wolfram Alpha can come in very handy. If you want to get your hands (moderately) dirty, my favourite tool is

Sage, which runs on the

Python programming language.

There are many excellent mathematical blogs worth following: I particularly recommend the blogs of

Gowers and

Tao, both for their regular interesting posts and their extensive list of other quality mathematical blogs.

## Non-Mathematical Links

Cryptic crosswords are great fun. There a lots of free ones to do at the

Guardian website and my helpful crossword solver website of choice can be found

here.

## Job searching

It can be difficult to find what positions are available in pure mathematics research. I've put together a page of useful links

here.