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This page represents only my own views, and not those of any university or other body. Posted Wednesday 14th July 2010 at 9.15pm Burkas and Brazil Ignore the first two paragraphs and Andy Hamilton's article on banning burkas in the Independent is a good one. The more pleasant news is that I'm in Brazil, at the Clay Maths Institute summer school. There's an obscenely packed schedule (talks from 9am till 8pm) but lunchtimes give a bit of time to explore the nearby beaches. Posted Tuesday 6th July 2010 at 1.04pm Some thoughts on giving talks I'm sat on a train and I was just thinking about giving talks. There is, of course, lots of advice available on how to give a talk, and I'm by no means an expert (although I have improved since my Pt III essay talk, where at one point I was waving at a blank blackboard in an attempt to explain something I had just rubbed out). But here are a couple of points - neither of which is new or profound - that I find it helpful to concentrate on. 1. Know what you are trying to do with your talk. Normally I'm talking to probabilists (fairly pure mathematicians). I generally hope that by the end of my talk, they will a) know what I've proved, b) think they understand the proof, and c) perhaps have learnt something. The "think they understand the proof" is the difficult part. I remember Tom Körner telling a story about an engineer friend of his who said, after watching the BBC Panorama documentary, that he thought he understood Wiles' proof of Fermat's Last Theorem - except for the details. Körner's point was that you don't understand a proof until you can do it fully yourself: the devil is in the details. And he's right, but when I'm giving a talk there isn't usually enough time or interest for the details. I actually want my audience to feel like the engineer - and perhaps, since they're mathematicians and many of them are cleverer than me, they can actually fill in the details themselves anyway. 2. Know how long your talk will take. If your talk is only supposed to be, say, 45 minutes long, then make sure you know that you can fit it into 45 minutes. It's no use thinking it'll be alright on the night - 45 minutes is 45 minutes is 45 minutes. I think of this a bit like understanding magic tricks. Often the reason people can't figure out how magic tricks are done is because they have some portion of their brain that wants to believe it's magic, and so suspends its usual logical rules (the Derren Brown episode where he "predicted" the winners of several horse races in succession is a good example of something that's obvious as long as you make the basic assumption that he doesn't actually have magical powers). Mathematicians give overlong talks because they want to believe they can fit in everything they want to say. Fit your talk into the time available, don't fit the time available around what you want to say. This one is, of course, pretty much the oldest piece of advice in the book, but it can't be overstated. It's not simplifying by much to say that if you overrun then almost everyone in the audience will be extremely unimpressed with both you and your talk! Posted Sunday 20th June 2010 at 1.12pm Fantastic This story made me think a bit more about what I said about the England fans before. We used to be known, as far as football went, as a nation of thugs and hooligans. The FA and the police have, over the years, done a great job of turning that around. English football fans now act a lot more like the Barmy Army of cricket fans - they get drunk, and there's a lot of mindless chanting, but it's now usually in the name of fun rather than animosity. The shoe-dancing that I mentioned below is just one example of brilliant spontaneity - I remember Portsmouth fans last season suddenly breaking out into mass star-jumping at Goodison Park. And at the cricket today, after England had hammered Scotland, 6 men dressed as gorillas chased a man dressed as a banana all the way around the ground. That's what live sport should be about - fun. As far as England's world cup performances so far go, from my obviously well-informed position it looks like we should wait and see how we get on against Slovenia. We've been rubbish so far, but thankfully that needn't matter a jot if we beat the Slovenlies by a few goals. Judging from their performance against the US, that's by no means a foregone conclusion - they're not a bad team, and indeed they did what we failed to do and beat Algeria - but their defence is dodgy under pressure. Time for Crouchy? Posted Saturday 19th June 2010 at 1.55pm Fifa fan fest There is a big screen here in Paris right by the Eiffel Tower that claims to be showing every game of the World Cup live. I saw the first England game (vs USA) there and it was good - the English fans showed up our monotonous one-chant French counterparts by inventively dancing with their shoes on their heads at the end even though England's performance was far from inspiring. But then I went yesterday to watch England vs Algeria, and the screen was just showing a pink message in French telling us that they would not be showing the game due to events beyond their control. There were a lot of staff standing around chatting to each other, but no attempt to let anyone know what was going on beyond the message on the screen. Obviously things can happen that might prevent them showing the game at the last minute, and no-one can do anything about that, but it might have been nice if there had been either some staff, or even some quickly-made posters, at the nearby metro stations warning people that they should turn around. As it was each of my friends and I wasted £2 on tube journeys and managed to see only the last 35 minutes of the match, and no-one has offered any explanation or apology. And there is no way of finding out whether the same thing is going to happen next week, for the now-crucial England-Slovenia game. Poor show chaps! Posted Saturday 19th June 2010 at 11.01am Complétez ce texte avec la préposition qui convient. Ils étaient venus _______ partout, _______ pied, _______ cheval, _______ voiture _______ rendre un dernier hommage _______ celui _______ lequel ils avaient mis tous leurs espoirs. Videos of the courses from the probability conference in Bath last year, "New random geometries and other recent developments in probability", by Frank den Hollander (Random polymers), Svante Janson (Random networks), Jean-François Le Gall (Random planar maps and continuum trees) and Yuval Peres (Markov chains, rates of escape, and embeddings) are available here. Mergepdf and Stress and Pie are great (in different ways). Posted Monday 7th June 2010 at 9.37pm New office I have a new office! It has walls, and a floor. And even a ceiling. Not much else though. It still confuses me that the French word for "office" is the same as the word for "desk". The secretary at work today said to me "There's the key for your bureau. But you don't have a bureau." (except entirely in French, of course) which, at first, surprised me a bit, until I realised that the first bureau meant office, and the second meant desk. Posted Friday 4th June 2010 at 12.18pm Maths and politics An amusing blog post from Tim Gowers. I think the first idea is a good one - probably with the alteration proposed by "Ori", that some proportion of votes are randomly exchanged, rather than changed, to avoid altering the total tally of votes. Tim Austin's thesis appeared on the arxiv today. I haven't read it yet but intend to at least make an attempt. Tim was the best mathematician in my year at Cambridge - he was known to us Clare mathmos as "Banach Space Guy" in our first year, as he would disappear from some of our lectures, allegedly to go to Part III lectures on Banach spaces. He has recently been awarded a Clay research fellowship, and was also the Sun newspaper "Mathematician of the year" in 2002! I spoke to him briefly a few times when we were doing Part III, as he was doing pretty much the same courses as me (including Ben Garling's course on operator semigroups, in which there were only three of us, plus Tom Körner and, for one lecture, Tim Gowers). Posted Thursday 3rd June 2010 at 4.18pm In a fist-fight with the fog Phew. Paris -> London -> Nottingham -> Birmingham -> Bristol -> Bath -> London -> Leeds -> Nottingham -> Grantham -> London -> Paris. Last week was pretty hectic. I did also spend some time not on the train or in the car - notably, I had a barbecue at my friend James' house, watched Somerset beat Worcestershire, watched England beat Mexico, passed my viva (thesis defense / soutenance de thèse for those outside the UK), was informed that I was organising the Bath maths postgrad Summer BBQ, played cricket for my old team in Bath, the Venturers, and danced a lot in Leeds. Thanks to everyone who put me up at any point during the week! Then since getting back I've been to watch Joanna Newsom, done the corrections for my thesis, and applied for a job. Joanna Newsom was, again, fantastic. And her band was tight. She played a second encore, which seemed genuinely not to be planned - they turned the stage lights off and the crowd lights on, and turned the background music on. And turned the background music up a bit because it couldn't be heard over the sound of the crowd clapping and banging things. And then turned it up some more, presumably in an attempt to get everyone to leave. Eventually Joanna came back out on her own and played "Sawdust and Diamonds". She did stumble on the words to her first song ('81), although not nearly so disastrously as last time I saw her, at Latitude festival, where she had to abandon "Sawdust and Diamonds" altogether because she couldn't remember the line "doubled over with the hunger of lions". High points were "Ribbon Bows", "Good Intentions Paving Company" (which basically panned into a jazz-style groove-out complete with massive trombone solo), and "Inflammatory Writ". This last one was a surprise for me - it's not one of the stand-outs on her first album, but the band really turned it into a storming pop song. I've just found this link to transcriptions of some JNew songs. Haven't tried them myself yet (the piano ones... I have no intention of trying to play the harp in the near future!) but they look good. Finally, inspired by Andy Zaltzman's "Lies About Cricketers", here are some Lies About Mathematicians taken from my special edition viva-passing parade email:
Posted Thursday 20th May 2010 at 6.18pm They're far more laid-back about their art galleries How prescient! Posted Monday 17th May 2010 at 11.44pm Worth duck-all and Useless What a difference a year makes. In the topsy-turvy world of the ICC, where world cups can turn up twice within 12 months, England managed to lose to the Netherlands in 2009, and then beat Australia (who featured as their strike bowler the man who spearheaded the Dutch attack those few months earlier) to become world champions in 2010. And some victory it was too - England dominated the tournament from the moment they sneaked through their first-round group. It's worth, then, revisiting that group stage and looking again at why England did only just manage to qualify. There was a rained-off game against Ireland, which no-one could do anything about - and for which points and run-rate were shared evenly. But there was also a rain-affected game against the West Indies, which England lost after Chris Gayle's side were set 60 runs to win from 6 overs in reply to England's 191 from 20. That is, West Indies needed a run rate of 10, only marginally above England's 9.55, even though they had to stretch their innings over a much shorter period with their full quota of 10 wickets to play with. "That doesn't seem fair," you might say - and Paul Collingwood agreed. From Cricinfo: "There's a major problem with Duckworth-Lewis [the system used to decide targets after rain delays] in this form of the game," Collingwood said. "I've got no problem with it in one-dayers, and I know it's made me very frustrated tonight because I've come off the losing captain, but it's certainly got to be revised in this form. "Ninety-five percent of the time when you get 191 runs on the board you are going to win the game. Unfortunately Duckworth-Lewis seems to have other ideas and brings the equation completely the other way and makes it very difficult." Actually, Paul, you're wrong. Currently the stats say that 100 percent of the time when you get 191 runs on the board you are going to win the game (or at least they did until the rain had its way in Guyana). But is that enough for Messrs Duckworth and Lewis? No way. Duckworth had this to say: "Remember that there have been a total of about 70 matches decided by Duckworth-Lewis since Twenty20 was invented in 2002, and there's only been two instances where any dissent has been expressed, and both of those were by Paul Collingwood and the England team, as a result of failing to win against West Indies." I'm afraid, Frank, that you're wrong too. In fact, Chris Gayle, the winning captain in Guyana, also had some harsh words for the system. "I think it's something they're going to have to look into. I would support what Collingwood just said. I could have been in the same position as well. It's something that can be addressed so it can be even stevens for both teams in the future. I'm happy but it's just unfortunate for England." Tony Lewis was rather scathing of England's claims too. Asked by the Indian magazine DNA about alternative suggestions, including reducing the number of wickets in hand for the chasing team, he simply said "I don’t think that would work at all. It’s a crude mechanism that would open up a lot of new problems." Burying your head in the sand hasn't been so popular since Duncan Fletcher's stubborn picking of GoJo and Gilo against all the evidence in the 2006/7 Ashes series. "I have always thought, in the modern game, that a spinner should be able to contribute runs down the order," he said. Thanks for that Fletch. Good evidence you backed it up with too. Just like Duckworth and Lewis. They tell us their method works well, but they don't give us any stats to justify their claims. Perhaps we can let Fletcher off on that front, as he had much of his success in other areas by picking on instinct. But for two statisticians it's just poor work and they shouldn't get away with it. Another, more reasonable tactic of Fletcher's was to look most critically at the make-up of the team not after they had lost, but after they had won. This England team's performances over the tournament have had few flaws. They were the best team by some distance. The only game they lost was the one in which they made their highest score - a score no international team has ever successfully chased down. I hope someone on the England management team remembers that - because the best time to complain about unfair treatment is now. By all means let's sing while we're winning - we don't often get the chance! - but let's make sure we have a bit of a moan too.
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