Author Archives: Robin Houston

Beyond Bézier curves

There is a new feature of Pages and Keynote, not mentioned in any of Apple’s publicity nor in any press coverage I’ve seen, that is really very interesting. Perhaps it will even one day prove to have been revolutionary, in … Continue reading

Posted in algorithms, Mathematics | Tagged , , | 23 Comments

I hate the Pumping Lemma

I hate the Pumping Lemma for regular languages. It’s a complicated way to express an idea that is fundamentally very simple, and it isn’t even a very good way to prove that a language is not regular. Here it is, … Continue reading

Posted in chatter | 45 Comments

The algebra of Unix command substitution

Shadab Ahmed raised an interesting question. Open a Unix command shell, type : ‘!!’ and press return. Then type : “!!” ‘!!’ and press return. Now repeat the following a few times: press the up arrow, and press return.

Posted in Mathematics | 6 Comments

“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

Linear Logic without Units

My PhD thesis (2007) was available for several years from my web site at the University of Manchester, but since that site was taken down it’s been unavailable. Today’s announcement is that I’ve finally got round to uploading it to GitHub.

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Puzzles like Adrift

Quite a few people were surprised by my description of Adrift as a “new game” – even though it was very new at the time – because they had seen similar games or puzzles before. You can read some of … Continue reading

Posted in chatter | 3 Comments

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

Posted in Mathematics | Leave a comment

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

Cartograms and the Carbon Map

Last night I gave a talk at geomobLDN about the carbon map project. Here are a few relevant links and tidbits.

Posted in Carbon Map, Kiln | Leave a comment