Category Archives: chatter

John H Conway and the invention of the filing cabinet

Conway is incredibly untidy. The tables in his room at the Department of Pure Mathematics and Mathematical Statistics in Cambridge are heaped high with papers, books, unanswered letters, notes, models, charts, tables, diagrams, dead cups of coffee, and the most … Continue reading

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The Prisoner’s Dilemma

The Prisoners’ Dilemma The Prisoner’s Dilemma is a game, but a game that seems to bear lessons for the conduct of human affairs more generally, and it has attracted a great deal of attention from men not noted for their … Continue reading

Posted in chatter, Mathematics | 23 Comments

Something all bash scripters need to know (and most of us don’t)

Calling all bash users. This is a public service announcement. Here’s something you need to know if you want to write bash scripts that work reliably, but you probably don’t.

Posted in chatter | 28 Comments

How to record a screencast video for free on Mac OS X

It’s hard to find any detailed information on the web about how to record a screen video without buying expensive software. I found out how to do it, so here I’m going to explain what I did for the benefit … Continue reading

Posted in chatter | 38 Comments

Challenging the Power of Twitter

Most of the time I use this blog to write about things I understand, so it was something of an experiment when on Sunday evening I wrote a short post about something I did not understand.

Posted in chatter, Mathematics | 2 Comments

Something I don’t understand about homomorphic encryption

Added later: In retrospect, now I know a little more about cryptography, I can see that my confusion here is caused entirely by the fact that I didn’t know the meaning of the technical term “semantic security”. Ever since Craig … Continue reading

Posted in algorithms, chatter | 6 Comments

Just occasionally, one would be quite lost without recursion

This was originally posted to Posterous in two parts, on the 23 and 26 August 2010. I don’t agree with all of it now, and I’m not sure it was worth writing in the first place, but I’ll keep it … Continue reading

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The category of Conway games

Several years ago I typed up a rough English translation of André Joyal’s hard-to-find 1977 paper Remarques sur la théorie des jeux à deux personnes, describing the category of Conway games. My version was on the web server of the University of Manchester … Continue reading

Posted in chatter | 8 Comments

Bad news for naïve sets

I’ve been fascinated by dialetheism ever since I first heard about it in 2005, from RM Sainsbury’s wonderful book Paradoxes. The pleasure I derive from the notion that contradictions can be true is, I admit, the same as the dizziness obtainable … Continue reading

Posted in chatter, Mathematics | 7 Comments


I’ve been thinking about restarting this blog for more than a year, but my plans to do so were always so ambitious that I never completed them: the charming essay Procrastination and Perfectionism is perhaps relevant here. I read somewhere that … Continue reading

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