Plus Blog
December 3, 2012
As we are having a little cake of our own today, we thought we'd look back on another great birthday celebration... Stephen Hawking turned 70 in January 2012 and to celebrate, the University of Cambridge put on a scientific conference as well as a public symposium. Plus went along, of course, and here are the articles and podcasts we have produced from the conferences. Happy reading and listening! A brief history of mine — This is an excerpt from Stephen Hawking's address to his 70th birthday symposium which took place on 8th January 2011 in Cambridge. From planets to universes — This is an article version of the lecture given by Astronomer Royal Martin Rees at Stephen Hawking's birthday symposium. It comes in two parts, the first is here and the second here. Happy birthday Stephen Hawking! — This is our brief report from Stephen Hawking's birthday symposium, which comes with a podcast featuring Martin Rees, some of Hawking's exstudents and his graduate assistant. Supergravity to the rescue? — In the corner of the garden between the Centre of Mathematical Sciences and the Isaac Newton Institute in Cambridge, sits a reminder of our ongoing quest to understand gravity: an apple tree that was taken as a cutting from the tree at Newton's birthplace, the tree that is said to have inspired his theory of gravity. Newton's theory was extended to the cosmological scales by Einstein's theory of general relativity – but can supergravity explain how gravity works in the quantum world? Find out in this interview with Renata Kallosh, which you can also hear as a podcast. Bang, crunch, freeze and the multiverse — Some of the things we overheard at Stephen Hawking's 70th birthday conference did make us wonder whether I hadn't got the wrong building and stumbled in on a scifi convention. "The state of the multiverse". "The Universe is simple but strange". "The future for intelligent life is potentially infinite". And — excuse me — "the Big Bang was just the decay of our parent vacuum"?! You can also listen to the accompanying podcast. 
December 2, 2012
Here at Plus we love everything Vi Hart produces. But her recent series on hexaflexagons (suggested by our good friend Sharon) is superb! In addition to the history of these mathemagical objects and how to make them (part 1 and part 2) there's a hilarious Hexaflexagon Safety Guide and our favourite, Tex Mex Hexaflexagons! Enjoy! 
December 1, 2012
Are you reading this page because you decided to or because you were destined to from the start of time? Plus shares Mick's sentiment that we are free to do what we want, any old time. But what does physics and mathematics have to say about free will? In one of our most mindbending yet enjoyable investigations (published in January this year), we spoke to philosopher of physics Jeremy Butterfield, quantum physicist Anton Zeilinger, cosmologist and mathematician George Ellis and mathematician John Conway to find out more. Freedom and physics — Most of us think that we have the capacity to act freely. Our sense of morality, our legal system, our whole culture is based on the idea that there is such a thing as free will. It's embarrassing then that classical physics seems to tell a different story. And what does quantum theory have to say about free will? Free, from top to bottom? — A traditional view of science holds that every system — including ourselves — is no more than the sum of its parts. To understand it, all you have to do is take it apart and see what's happening to the smallest constituents. But the mathematician and cosmologist George Ellis disagrees. He believes that complexity can arise from simple components and physical effects can have nonphysical causes, opening a door for our free will to make a difference in a physical world. John Conway: discovering free will (part I) — On August 19, 2004, John Conway was standing with his friend Simon Kochen at the blackboard in Kochen’s office in Princeton. They had been trying to understand a thought experiment involving quantum physics and relativity. What they discovered, and how they described it, created one of the most controversial theorems of their careers: The Free Will Theorem. John Conway: discovering free will (part II) — In this, the second part of our interview, John Conway explains how the KochenSpecker Theorem from 1965 not only seemed to explain the EPR Paradox, it also provided the first hint of Conway and Kochen's Free Will Theorem. John Conway: discovering free will (part III) — In the third part of our interview John Conway continues to explain the Free Will Theorem and how it has changed his perception of the Universe. 
November 15, 2012
Make your childhood dreams come true and join the Paris Fire Brigade as part of the 201213 Mathematical Competitive Game. This year's game is brought to you by the French Federation of Mathematical Games, Société de Calcul Mathématique SA as well as The Paris Firemen Brigade and is open to anyone to enter either individually or in groups. The previous games have also all been based on real life problems – designing a bus or electricity network or searching for the best car itinerary in partnership with transport or electricity companies – and solving them usually takes several months of work. This year's game is to decide how best to use your limited resources of firefighters and equipment to fight fires and minimise their damage across the whole of Siberia. This huge region is broken up into cells defined by latitude and longitude, so these vary in size as well as the their level of population and landscape. There are mathematical descriptions of the ways the fires start, spread and the damage they cause as well as for modelling your firefighting capacities and the way they can combat the fires. Your job is to decide how to distribute your firefighters and specially equipped planes and then estimate the cost from damage from the fires in one summer, the cost of your firefighting strategy and the probability that your strategy to keep costs to this level will work. And there's not only mathematical glory and the gratitude of Siberia on offer, there's also up to 500 Euros in prizes for the winners. You can find the details of this year's competition here and download the data. Good luck! To get you thinking about how you can mathematically model fires, read our article Matrix: Simulating the world Part II about simulating the spread of forest fires using cellular automata.. The example below has either bare earth (grey squares) or trees (green squares), with squares turning green as new trees grow. Tree's catch fire (and their squares turn orange) as a result of lightning strike and the fire spreads to all adjoining squares with trees. This text is usually replaced by the Flash movie.

October 31, 2012
This is a visual representation of the Lie group E8, which encodes the symmetries of a 57dimensional geometrical object. Find out more here. Image: Claudio Rocchini. Tomorrow, 1st November 2012 at 4pm GMT, Plus will be part of a MOOC (massive open online course)! For an hour we will be talking about the beautiful subject of symmetry in a way that is accessible to everyone and there will be questions and answers too. This online talk is open to everyone and it's free. To join, register here. We will explore a range of symmetry topics, from the beautiful patterns in the Alhambra to mathematical group theory and symmetry breaking in physics. This talk is part of a whole series called VizMath which explores the many images of maths, from crocheted hyperbolic curves to the mathematics of origami. VizMath was created by Betty HurleyDasgupta and Carol Yeager and it's published by SUNY/Empire State College, USA. Come and join us!
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October 26, 2012
Date: Tuesday 20 November 2012, 6.30 pm Venue: Centre for Mathematical Sciences, Clarkson Road, Cambridge CB3 0WATickets: Entry is by ticket only, £7.50 each. PLEASE NOTE THAT TICKETS FOR THIS EVENT ARE NOW SOLD OUT.We're very excited to be hosting the UK premiere of acclaimed indie film Travelling Salesman, a mathematical thriller imagining the consequences of solving the P vs NP problem. Travelling Salesman is an intellectual thriller set in a fictional reality where four brilliant mathematicians solve the P vs NP problem, one of the hardest open problems in maths with profound implications for computer science and cryptography. Offered $10 million dollars by the US government for exclusive access to the solution, they must grapple with the practical and moral repercussions of discovering a proof that P = NP. (Find out more about the P vs NP problem here.) This is the first time that Travelling Salesman has been shown in the UK. The screening will be prefaced by a short introductory talk by Professor Jonathan Oppenheim (UCL) and will be followed by a live Q&A session with the writer/director, Timothy Lanzone. Entry is by ticket only (£7.50 each  please note the event is now sold out). The event will start at 6.30 pm, and should finish by 8.30/8.45pm. See the official Travelling Salesman website. "It is not often that espionage thrillers feature a round of peer review, but this early scene is a natural fit for Travelling Salesman, a film based on the premise that the biggest unsolved problem in computer science has been cracked. ... P = NP ... is a great premise that writers Andy and Timothy Lanzone use to explore the theme of scientific hubris. Travelling Salesman’s mathematicians are all too aware of what their work will do to the world, and watching them argue how to handle the consequences offers a thriller far more cerebral than most." New Scientist 