Simple City

John Derrick

Richard — Fri, 10 Feb 2012 15:12:25 +0000

I meant to post something about John Derrick, a long-standing and much loved member of the logic group at Leeds University, who died in December. I only knew John in his later years (some time after his official retirement), but would regularly see him at the Wednesday afternoon logic seminar, which was often followed by a trip to the pub. He was always a thoughtful and benevolent presence in the seminar room, and made for entertaining and knowledgeable company over a drink.

For younger members, he was also something of a link to an earlier era, the days when the group was led by Martin Löb (of Löb’s theorem fame).

It is a testamant to his strength of character, and his love of the subject, that he continued to attend and contribute to these seminars through many year of ill-health, up until only a few weeks before his death.

An obituary by Garth Dales appeared in the LMS news-letter and a longer one can be read on the University of Leeds website.

Me, Elsevier, and the New Scientist

Richard — Wed, 08 Feb 2012 10:31:45 +0000

In my last post I said that I had added my name to the growing anti-Elsevier boycott at The Cost of Knowledge.

I need to add something to that, since Yemon Choi has pointed out that the New Scientist magazine, for whom I have done (paid) work in the past (listed here), is owned by Reed Business Information, part of the Reed-Elsevier group.

So am I going to refuse further (paid) work for the New Scientist? It’s a perfectly fair question. My answer is no.

Here is some self-justification: I like the New Scientist as a magazine. Granted, it’s had its share of problems in the past. But overall I believe that it is – in and of itself – a force for good in the world. I regret that RBI is a stable-mate of Elsevier.

I’ll readily admit that there is self-interest at work here too. I like to write about progress in the mathematical sciences. I like my articles to reach a broad audience, and, yes, I also like getting paid.

There are very few outlets where a story about mathematics can be written at reasonable length, without being excessively dumbed down (hopefully!), reach a decent number of people, and earn the author a few quid. So I’m not willing, at this stage, to cut myself off from the biggest one in the UK.

Having said all this, I believe that I can, in good faith, remain a signatory to The Cost Of Knowledge. This is a space to “declare publicly that you will not support any Elsevier journal”. I understand this as referring to academic journals pulished by Elsevier, rather than magazines published by RBI. Certainly the discussions that I have read around the petition seems to reinforce that interpretation. However, I would be happy to reconsider my position if anyone can make a strong case that I’m guilty of having my cake and eating it.

Let it be known that…

Richard — Mon, 06 Feb 2012 14:18:29 +0000

…I have just signed the Cost of Knowledge petition.

I don’t think I need say any more, since the issues have been thoroughly discussed elsewhere.

Pick’s Theorem & Ehrhart Polynomials

Richard — Wed, 01 Feb 2012 16:01:08 +0000

Pick’s theorem is a simple, beautiful, and usful fact of elementary geometry. It should be much better known than it is! In fact, I have half a mind that it should be on the A-level (high school) syllabus.

Less famous – but equally wonderful – are Ehrhart polynomials, which are what you get when you try to lift Pick’s theorem into higher dimensions. Though geometrically intuitive, they quickly lead into deep mathematical waters. They’re also valued as tools in optimisation problems and in other areas of computer science (I’m told).

This afternoon I gave a – hopefully fairly accessible – talk on these topics. The slides are available here.

(Update: PDF of slides here).

Elwes Elsewhere

Richard — Wed, 07 Dec 2011 13:22:15 +0000

If it’s been quiet around here recently, it’s because I’ve been hanging around in various places other than my own blog recently…

1. I’m on Google+ a lot these days. It’s now definitely my social medium of choice. Come and join in!

2. Coming out of discussions on G+, I cowrote a piece with John Baez on Babylonian mathematics and the square root of 2, which is now up on John’s blog Azimuth. (I can’t resist adding that John was also kind enough to write a flattering review of Maths 1001.)

3. And by no means least… I have a new book out! It’s called The Maths Handbook. I’ve been chatting about it, and maths in general, with Daniel Fraser on the Quercus Couch.

Ultimate L

Richard — Thu, 28 Jul 2011 09:56:51 +0000

I have a feature article in this week’s New Scientist magazine, about the Continuum Hypothesis, set theory, and Hugh Woodin’s Ultimate L. It’s in the shops, or here. [£]

Russell on Thought

Richard — Fri, 24 Jun 2011 22:32:15 +0000

“Men fear thought more than they fear anything else on earth – more than ruin, more even than death. Thought is subversive and revolutionary, destructive and terrible; thought is merciless to privilege, established institutions, and comfortable habits; thought is anarchic and lawless, indifferent to authority, careless of the will – tried wisdom of the ages. Thought looks into the pit of hell and is not afraid. It sees man, a feeble speck, surrounded by unfathomable depths of silence, yet bears itself proudly, as unmoved as if it were lord of the universe. Thought is great and swift and free, the light of the world and the chief glory of man.”

— Bertrand Russell (Why Men Fight)

Topological Limericks

Richard — Tue, 21 Jun 2011 20:03:34 +0000

A mathematician confided
That the Möbius strip is one-sided
And you’ll get quite a laugh
If you cut one in half
For it stays in one piece, undivided!

- Anonymous via @ColinTheMathmo

A mathematician named Klein
Found the Möbius Loop quite divine
Said he, “If you glue
The edges of two
You get a weird bottle like mine!”

- Anonymous

The topological part of my brain
Finds Möbius strips quite a strain
But I make you this pledge:
I’ll glue one at its edge
And build a real projective plane

- RE

Any more? (Or can anyone give me attributions for the Anons?)

Ugliness and masturbatory definitional runarounds

Richard — Thu, 09 Jun 2011 15:16:28 +0000

If you haven’t read A Mathematician’s Lament, Paul Lockhart’s gloriously polemical assault on

the confused heap of destructive disinformation known as “the mathematics curriculum”

then I strongly encourage you to put that right.

The focus of Lockhart’s ire is mathematics in the US school system, but it translates without difficulty to the UK and probably a great many other places.

Lockhart doesn’t diagnose the cause of this mathematical malady, but I will offer one thought: the take-over of exam results as the be-all and end-all of educational attainment.

If you fancy discussing this issue further, there’s a webinar on the topic over at MathFuture this evening, hosted by David Wees and Richard DeMerchant.

An Idiotic Paradox

Richard — Mon, 06 Jun 2011 15:09:06 +0000

A. B-san, may I aks you a question?

B. Please do.

A. Thank you. Are you an idiot?

B. That question is hardly of the intellectual calibre that I have come to expect from you, but I shall answer it nevertheless. No, A-san, I am not an idiot.

A. Are you entirely sure? I believe that I can demonstrate that you are indeed an idiot.

B. Are my trousers unbuttoned? Have I forgotten your birthday? If I have made some careless mistake you could tell me kindly rather than with insults.

A. Other than being somewhat old and ill-fitting, your trousers are fine. And my birthday is not for 3 months, as I believe you know. I do not have any such mistake in mind. Rather, I claim that I can demonstrate that you are an idiot using only this pen and paper. What is more, you will be forced by your own words to accept it. May I try?

B. I suppose so.

A. Very well. I shall write a sentence on this paper, and you must tell me whether or not you believe it.

B. What if I don’t know?

A. If you don’t know, then say you don’t believe it.

B. Hmm. It’s going to be one of those sentences which asserts its own falsity, isn’t it? Like that Cretan who said “all Cretans always lie”. Utterances like that can’t sensibly be called either true or false.

A. A good point, but my sentence is fully capable of supporting a truth value. Indeed, I shall attempt to persuade you that the sentence is true. And very likely I shall succeed. Nevertheless you will continue to insist that you do not believe it.

B. What? You say I will be convinced of your sentence’s truth, but at the same time I will refuse to believe it? That would indeed make me a supreme idiot.

A. Exactly! [Writes something down and hands it to B.]

B. [Reads] “Only idiots believe this sentence.”

A. So, do you believe it?

B. If I believe it, then I must be an idiot.

A. Precisely!

B. But I maintain that I am not an idiot. So, no, A-san, I do not believe this sentence.

A. That’s what I said when I first read it. And that’s what C-san and D-san said too. In fact, I expect your reaction is the same as that of any intelligent person.

B. I agree. Anyone who read that sentence and declared that they believed it would be a self-admitted idiot.

A. In other words, B-san, you are saying that only idiots believe that sentence.

B. Yes!

A. Ok! Now read it again.

B. [Reads it again. Thinks.] Bollocks.

A. And B-san?

B. Yes?

A. Your trousers are undone.