Category Archives: Mathematics

“Venn diagram” partitioning

Paddy3118 wrote about partitioning elements in the same way a Venn diagram does. So, if we have sets A, B and C, the partitions are

Posted in algorithms, chatter | 1 Comment

Adrift is NP-complete

There’s a lovely new puzzle game for the iPhone called Adrift. I got it last week when I was in bed with flu, and it’s a fun way to spend a few hours. The puzzles look like this: And you … Continue reading

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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

On editing text

Editing text is the opposite of handling exceptions; or, to put it another way, editing text is like exception handling but backwards in time. I realise this is an unexpected claim, so I hope you will permit me to explain. … Continue reading

Posted in algorithms, category theory | 17 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

Computing Fibonacci numbers using Binet’s formula

A few months ago I wrote something about algorithms for computing Fibonacci numbers, which was discussed in some of the nerdier corners of the internet (and even, curiously, made it into print). Several people suggested that Binet’s closed-form formula for … Continue reading

Posted in algorithms, Fibonacci numbers, Mathematics | Tagged | 9 Comments

Counting small mazes

Before we get into general algorithms for counting mazes, I thought it would be interesting to do some small cases by hand. It’s quite fun to do, and it’ll give us a few numbers to check against the results of … Continue reading

Posted in mazes | 3 Comments

Counting mazes: before we begin

If you’re following the maze series, I hope you’re persuaded that thinking about how to count mazes is a reasonable line of attack on the random access problem.

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