Category Archives: meta

How to explain the principle of inclusion-exclusion?

I’ve been remiss in finishing my series of posts on a combinatorial proof. I still intend to, but I must confess that part of the reason I haven’t written for a while is that I’m sort of stuck. The next … Continue reading

Posted in combinatorics, meta | Tagged , , , | 7 Comments

I’ll be hosting the Carnival of Mathematics, and the submission deadline is coming up soon—Tuesday, May 1. Please submit something! It could be something you wrote, or something someone else wrote that you enjoyed. All mathematics ranging from elementary to … Continue reading

Posted on by Brent | Comments Off on Carnival of Mathematics submissions due in a week

New Carnival of Mathematics

The Carnival of Mathematics has been revived! A big thanks to Mike Croucher of Walking Randomly for organizing it for the past few years, and to Katie Steckles, Christian Perfect, and Peter Rowlett for taking over. The latest edition, carnival … Continue reading

Posted in links, meta | Tagged | Comments Off on New Carnival of Mathematics

Four-figure offer

This just arrived in my inbox: My name is Becky Raymond, I’m a Domain Brokerage Consultant working on behalf of the owner of to sell this premium asset. While searching online I came across your domain; since both … Continue reading

Posted in humor, meta | Tagged , , | 7 Comments

Old posts fixed

When I moved this blog from my own custom WordPress installation to last March, the formatting, , and images on a number of old posts got screwed up. I have finally finished going back through all my old posts … Continue reading

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Collatz conjecture: an apology

In the comments on my previous post about Gerhard Opfer’s proposed proof of the Collatz conjecture, several different people expressed the opinion that my tone was rather arrogant, and I think they have a point. So: I apologize for my … Continue reading

Posted in meta, open problems, proof | 9 Comments

Moved to

I spoke too soon before — over the past several weeks I’ve continued to have problems with my hosting, so I finally bit the bullet and transferred everything to (the URL of my blog is the same as before … Continue reading

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My blog is back (hooray!) and a quick puzzle

My blog is finally back up after a long hiatus due to hosting problems (not the first time). I’m seriously contemplating moving somewhere more reliable, but it’s hard to come up with a solution that would not (a) invalidate any … Continue reading

Posted in logic, meta, puzzles | Tagged , , , | 8 Comments

Back in business

I had some hosting issues for a while there but should be back in business now. The database had to be restored from a backup so I lost my most recent post, but had the text of it saved elsewhere … Continue reading

Posted in meta | 1 Comment

Perfect age

Today is my birthday! This is the second and (barring any miraculous advances in medical science) final time that my age will be a perfect number. Unfortunately, the first time my age was a perfect number, I didn’t know what … Continue reading

Posted in meta | Tagged , , | 15 Comments