“…There are two different ways of writing history: one is to persuade men to virtue, the other is to compel men to truth”

The lesson is clear; it doesn’t really matter about the truth if you tell a good story. Not a surprising sentiment to find in a historical novel, it even goes as far to call mere truth-tellers:

“undertakers who lay out the corpse of history”

But should we ignore what really happened, for the sake of a good story? That surely depends on why we’re telling the story and whether the changes in Graves’ terms persuade us to virtue.

We tell stories not only for their entertainment value, but also to explore human experience. The virtue that arises from telling historical stories lies in its ability to make us reflect on contemporary issues and make them better. If positive change becomes less likely because the history has been altered to make it more dramatic then we should be critical of the alteration. We also have a responsibility towards people who cannot speak for themselves. It is not enough to just know someone’s name because of a story.

Whenever I talk to people about Egyptian mathematics I have to deal with the stereotypes of ancient Egypt before I can address the interesting mathematical fragments that they left behind. Popular culture represents ancient Egypt as a death obsessed, mystical culture. This view is contrary to the picture of their mathematics which shows a highly organised state with complicated state structures and a love of precision. You may think that *The Mummy* was just a harmless bit of fun, but films like this lead to a prejudicial view of ancient Egypt that is hard to overcome. Surely we should protect the memories of real people, especially if they are long dead?

If we want people to be inspired by the history of mathematics then we need to be careful that its representation is socially and culturally inspirational. The portrayal of mathematicians, both real and fictional, in films and TV shows is one of a set of people who are odd. They are usually loners with no social skills and overwhelmingly men, too wrapped up in solving. Does it drive us to virtue to continue with this meme? Does it encourage more people to become maths enthusiasts?

Seeing a film with known inaccuracies will always leave me feeing lied to and tricked. No amount of dramatic pauses, fabulous costumes and stunning performances will ever make up for it. To want real people to be portrayed honestly and accurately is not pedantry, just as wanting facts to be displayed accurately on a graph is not.

The standard comments I get when sticking up for people from the past is that I should lighten up, I’m dismissively told that perhaps I should just go and watch a documentary. I’ve never understood why people think that this is somehow a lesser option – it sounds like an excellent plan!

]]>The Carnival rounds up maths blog posts from all over the internet, including some from our own Aperiodical. See our Carnival of Mathematics page for more information.

]]>Puzzlebomb is a monthly puzzle compendium. Issue 36 of Puzzlebomb, for December 2014, can be found here:

Puzzlebomb – Issue 36 – December 2014

The solutions to Issue 36 will be posted at the same time as Issue 37.

Previous issues of Puzzlebomb, and their solutions, can be found here.

]]>Sometimes maths can make a very clear point about a complicated subject.

Vi Hart, internet mathematician, has worked with games designer Nicky Case to put together this lovely playable blog post, Parable of the Polygons. It’s based on a mathematical model by economist Thomas Schelling, and it’s about social behaviour, and how personal bias, even in small amounts, can lead to much greater systematic bias and segregation on a large scale. Nothing can explain it as well as itself, so play through each of the steps and see how the maths works for yourself.

Vi has herself been surprised at how strongly positive the reaction to the project has been – despite being maths-based, and a possibly slightly critical comment on all of our own attitudes, it’s had a huge amount of attention on Twitter, and all the feedback she’s had has either been positive, or a feature request.

The post has already been translated into Spanish and Brazilian Portuguese, and Github users with other languages would be welcome to chip in. It’s all available for forking on Github.

]]>Here’s one of my favourite maths puns.

What’s yellow and equivalent to the axiom of choice?

Zorn’s

Lemon!!!!!!!!

I like it because it’s a real groaner, but to even begin to see what it’s punning on you have to know some pretty obscure facts about set theory. That makes it an ideal maths pun.

Maths puns abound (both upper and lower). Most of the time they make your eyes roll so badly that gimbal lock becomes a consideration, but a real corker makes all the years of mathematical study worthwhile.

Since the year is about to end, we thought it’d be a fun idea to collect some new maths puns, and run a quick competition to find 2014’s best offering (or the local maxipun at 2014, as we like to call it).

The rules are simple: tell us a pun, give a citation if it’s not your own work, and give us a way of identifying you in case you win. We’re looking for **new** puns, so anything seen in the likes of Dundes *et al.* is obviously off-limits.

We’ll keep the submissions form open until Friday the 19^{th} of December, and then we’ll pick a winner and publish the results some time before the new year. The winning entry will, geography allowing, receive a * fabulous prize* of $\approx \epsilon$ value.

And so, without further ado: get punning!

(if that form doesn’t load for any reason, load it directly by clicking here)

]]>Let’s start with the Prime Number Checker. It’s a text box that tells you the prime factors of any number (integer greater than one) you type into it. The guts of the source code is in this file on GitHub, and there are two things I like in there. First, the same thing can be done in a single line of code:

for (var p=[], m=2; n>1; m++) for (; !(n%m); n/=m) p.push(m);

You should not do it that way. (If you must, you should at least space it onto three lines.)

The second thing I like is that the entire algorithm is in there twice, and the reason is fairly interesting. Matt’s book mentions binary, and how computers encode numbers, and that’s sort of why I needed two versions of this algorithm. The first uses actual numbers, stored in binary inside the computer and processed as such by the CPU. That works really well up to about nine million billion, after which there are no prime numbers. Since we know there are actually an infinite number of them (and have found some) clearly something’s gone wrong.

The problem is that Javascript stores numbers of that size as ‘floating point’ numbers – essentially scientific notation in binary. A number might be stored as $1.00101101 \times 2^{10011011}$. After nine million billion, it runs out of digits in the main part of the number and has to start increasing the exponent instead. This works great for almost every conceivable purpose, except of course that any number in that form divides by $2$.

In Python that’s no problem because it will happily deal with infinite strings of binary numbers, but the pleasingly absurd Javascript solution is Big.js, a complete rewrite of numbers, which allocates as much memory as it needs and can in principle store any size number exactly, with all its prime factors intact. (In practice, of course, it uses regular numbers to index the array and would therefore conk out somewhere below ten-to-the-nine-million-billion.)

The most complex of the various toys and gadgets, because I got a little carried away, is the Polygonal Number Calculator. This will take a number and tell you if it is (say) a triangle number, a hexagon number, or a prime — and it will demonstrate this fact by arranging the dots into a triangle or a hexagon. The source is split across a few files, but most of the maths is in the property checker and the dance generator.

There’s some tricky hidden maths in here. For example, I wanted to make sure that nearby dots would usually be different colours, no matter what shape I arranged them in.

If you read the chapter about turning a photo into a spreadsheet, you know computers show colours as red, green and blue dots. If you’re read any other sentence at all of the book, you’ll probably be comfortable thinking of those as three dimensions of a cube, where a colour is simply a point within the cube. If we don’t mind spinning and bending that cube, we can use any 3D coordinate system we want to describe a colour. We can even jump into polar coordinates and think of colour as a cylinder, with the rainbow around the circumference (with red and blue joined up by magenta, largely to annoy Steve Mould). To generate the dot colours, I just move around that circular rainbow by a set angle each time.

But what angle? $90°$ would repeat after four dots, which is plainly no good. In fact, any rational number would repeat eventually. And any number *near* a rational isn’t ideal – $\pi$ is irrational, but $360\pi°$ would make roughly $22$ rotations after $7$ dots and nearly repeat. We need the most irrational number there is and, insofar as such a thing exists, the best candidate is $\phi$.

I set the dots to each be $360\phi°$ further around the hue wheel than the last (or maybe I used $\frac{360°}{\phi}$ – I can’t remember, and the weird thing about $\phi$ is that it doesn’t matter) and the result is that apart from some funky stripes around Fibonacci numbers, the dots largely behave and you don’t notice much structure to them.

There’s also a bonus gadget just for you guys, which lets you play with the angle and see if you can find a nicer arrangement of colours. You can choose an angle step, and then highlight every $p$ dot to see if you can see clear lines, which will appear as stripes and blocks in our dot patterns. The hue wheel with $\phi$ as the angle step creates a familiar sunflower image, and by setting $p$ to Fibonacci numbers you can see the seed spirals, which map exactly to the stripes we saw earlier. I never understood before making this why the spirals came in Fibonacci numbers, but now I do: if every $13$th seed makes a spiral, then there must be $13$ such spirals – increase the $i$ spinner to see them all.

Speaking of Fibonacci dot patterns, the Fibonacci numbers are represented by the classic Fibonacci spiral, but to be honest this is slightly a fudge: the number of dots is essentially the total length of the spiral, but normally you start with no spiral and add each Fibonacci term as you go, which is elegant and beautiful, but *not what we want*.

$n$ | $n$^{th} Fibonacci number |
Length of spiral |
---|---|---|

1 | 1 | 1 |

2 | 1 | 2 |

3 | 2 | 4 |

4 | 3 | 7 |

5 | 5 | 12 |

None of those spiral lengths are Fibonacci numbers, although they are all one less than a Fibonacci number. I genuinely don’t know if that pattern will continue forever. Luckily, the differences between them all *are* Fibonacci numbers – obviously – and the difference between two Fibonacci numbers is also a Fibonacci number: $F_n = F_{n-1} + F_{n-2}$, so $F_n – F_{n-1} = (F_{n-1} + F_{n-2}) – F_{n-1} = F_{n-2}$, which is sort-of obvious too. All I need to do is to fudge the start of the spiral so that adding the $n-2$^{th} Fibonacci number will give us $F_n$ dots. That fudge turns out to be squeezing in an extra dot before the spiral kicks in, which means that the pattern in our table earlier *does* continue forever. Hey, we learned something together: $\sum_{i=1}^{n} F_i = F_{n+2}-1$.

There’s also a little light geometry that went into working out how far apart dots could be in each pattern, and the fact that the whole thing runs on computers which are basically maths with keyboards, but I think I’ve already gone on too long, so I will leave you to play with the remaining gadgets (including a deleted scene that didn’t make the book) and peek at the source code.

]]>My title is: ‘The unplanned impact of mathematics’ and its implications for research funding: a discussion-led educational activity.

Abstract:

‘The unplanned impact of mathematics’ refers to mathematics which has an impact that was not planned by its originator, either as pure maths that finds an application or applied maths that finds an unexpected one. This aspect of mathematics has serious implications when increasingly researchers are asked to predict the impact of their research before it is funded and research quality is measured partly by its short term impact.

A session on this topic has been used in a UK undergraduate mathematics module that aims to consider topics in the history of mathematics and examine how maths interacts with wider society. First, this introduced the ‘unplanned impact’ concept through historical examples. Second, it provoked discussion of the concept through a fictionalized blog comments discussion thread giving different views on the development and utility of mathematics. Finally, a mock research funding activity encouraged a pragmatic view of how research funding is planned and funded.

The unplanned impact concept and the structure and content of the taught session are described.

Rowlett, P., 2015? ‘The unplanned impact of mathematics’ and its implications for research funding: a discussion-led educational activity. *BSHM Bulletin: Journal of the British Society for the History of Mathematics*. DOI: 10.1080/17498430.2014.945136.

**Theorem:** You can turn any shape into a rabbit by adding a face, ears and a tail to it.

**Proof (by construction):**** **geobunnies.com

This is delightful. There’s a new school of Platonism, one which believes that not only do ideal shapes exist, so do the bunnies inside them.

Joy!

]]>The answer to this question is a cultural one. We can put aside the question of whether mathematics itself is ‘real’ or not. The names we give to the people that do maths, and how they are organised and paid for is an entirely societal and cultural question. For me, the question of how mathematicians are recruited, trained and regarded by society should be one of the main research goals of the history of mathematics.

My membership of the Institute of Mathematics and its Applications is at the affiliate level. Anyone can join at this level; you’ve just got to want to. My degree and professional experience is not suitably mathematical to warrant membership at a higher grade. So according to a professional body I can’t really call myself a mathematician, although they would certainly agree that I was an enthusiast.

Yet in my professional life I am seen as a maths expert. When schools in my region are looking for something exciting to do with maths they get referred to me. I have even written a book about encouraging gifted pupils in mathematics. Is this just because I can talk a good talk and write good funding applications, or is there something else going on?

I work with the STEM ambassadors programme, I work with teachers on what they can use STEM ambassadors for in schools and I am always trying to sign up interesting people to the scheme. There are tens of thousands of people signed up across the UK. Ambassadors select their own expertise when they sign up for the scheme and only 5% of those people chose mathematics (the choices being Science, Technology, Engineering and Mathematics). Where are all the mathematicians?

Even amongst highly trained professionals there is a reticence to identify as a mathematician and an expert on the subject. Why? The reasons are many and complex, but it has to be partly cultural and about how we see ourselves. The mathematician’s love of the abstract and penchant for arcane symbols marks the in-group from the out-group. It is enchanting to some, excluding for others.

I have no problem calling myself a street dancer, although you’re not going to see me on a stage anytime soon. My greatest achievement in dancing is to be highly commended in my silver medal exam. Enthusiasm and time spent in a dance studio is enough, it’s not just based on ability. So yes, I do think I’m allowed to call myself a mathematician. The enthusiasm is certainly there, I’ve flung my arms around wildly to explain something, and more than one beer mat has sacrificed its life in the pursuit of a better diagram. I spent time over the weekend learning how to work out the square root of a polynomial (go on – test me!). This is why I am comfortable calling myself a mathematician, it is through the company I keep and the culture I am steeped in.

]]>What’s everyone’s favourite fictional mathematician?

— Katie Steckles (@stecks) November 10, 2014

The response was overwhelming. Here’s a guide to the non-existent number crunchers you should know about, and some you probably already do.

The most popular response by far, and actually the person I was thinking of when I asked the question, is **Ian Malcolm** from the *Jurassic Park* series of novels/films. He’s played by Jeff Goldblum in the film versions, and is an expert in chaos theory. The author, Michael Crichton, was apparently inspired by real-life mathematicians Ivar Ekeland and James Gleick, and the character spends a lot of time pointing out that (SPOILER ALERT) if you create something as unpredictable and uncontrollable as a park full of dinosaurs, the results will tend towards the chaotic – maybe you don’t need to be a chaotician to work that out, but it’s great to see a mathematician in film that’s actually cool and doesn’t conform to the usual stereotypes.

The character is also responsible for the novel having an iteration of a fractal printed at the start of each chapter (see below) – it’s the Harter-Heighway Dragon Curve, sometimes called the Jurassic Park fractal, and it increases in complexity as the events in the story get more and more uncontrolled.

Our second most popular choice was the arch-nemesis of everyone’s favourite abductive logician, Sherlock Holmes. **Professor James Moriarty** has been portrayed numerous times in TV and film since the original novels by Sir Arthur Conan Doyle, and it’s not always emphasised that his original training was as a mathematician – although in ‘The Final Problem’, Holmes describes Moriarty as having “a phenomenal mathematical faculty”, and says “he won the mathematical chair at one of our smaller universities”. Even though Moriarty is entirely fictional, and Conan Doyle never elaborated on its contents, Moriarty’s book ‘A Treatise on the binomial theorem’ has its own Wikipedia page. Moriarty’s mathematical work is discussed in a 1989 piece at New Scientist (subscription required), and for the 2011 film *Sherlock Holmes: A Game Of Shadows*, a team from Oxford University were engaged to write some convincing mathematics for the production, including a code based on Fibonacci numbers – further detailed in a PDF at SIAM.

If you’ve read Isaac Asimov’s *Foundation* series of books, you’ll recognise the name **Hari Seldon** – he’s a mathematician who predicted the future using a combination of history, sociology and statistical probability. He and his work are featured throughout the series, which comprises a total of seven novels set in the same universe. The original trilogy was accompanied by two sequels and two prequels; in them Seldon predicts the downfall of the Galactic Empire, and takes steps to ensure the future of humanity and its collective knowledge.

Fans of the series will also be excited to hear about the upcoming TV adaptation…

From the 1992 novel * Uncle Petros and Goldbach’s conjecture*, reviewed at the MAA website by Keith Devlin, in which a young boy gets to know his reclusive uncle, who’s trying to prove that every even number can be written as the sum of two prime numbers. Apparently, when the book was published in the UK/US in 2000, the publishers announced a $1m prize for anyone who could prove the conjecture within two years – which nobody did.

Protagonist of the Darren Aronofsky film Pi, in which **Max**, a paranoid mathematician, works out some frankly unbelievable maths which allows him to predict the stock market, and is chased by shady mafia types, Wall Street financiers and Hasidic Jews, until he removes the knowledge from his own brain using a [spoilers].

**Charlie Eppes** is the lead character in TV mathematical police procedural drama (police algorithmical?) *Numb3rs*; he is a mathematician, and also the brother of an FBI agent, and together they fight crime. It’s exactly as bad as it sounds.

The main protagonist of James Joyce’s *Ulysses*, **Leopold Bloom** is rarely described in synopses as being a mathematician – although it is mentioned in Chapter 17 that he spent some of 1886 ‘preoccupied with the problem of the quadrature of the circle‘.

In the *Dune* series of novels, the **Spacing Guild** are responsible for making the necessary calculations to allow faster-than-light travel by the universe’s space ships. Powered by the ubiquitous ‘spice’ which is central to the economy, and vital for interstellar trade and travel, mastering these spacecraft puts the mathematicians in a highly respected position. Basically, everyone’s nice to the mathematicians because without them everything would go badly wrong. Much like in real life.

Literally nobody will remember who this is from the name, but if I say **‘Samuel L Jackson’s character in the movie Sphere’**, literally two people will then know who I’m talking about. Adapted from the Michael Crichton novel, the 1998 sci-fi thriller featured another cool movie mathematician (could he fail to play a character that’s cool?) sent as part of a team to investigate a mysterious spaceship from the future that’s crashed on the bottom of the ocean.

**Adams** quickly determines (using mathematician logic) that since the ship has travelled back in time, and the ship’s log records the incident which sent them back as an ‘Unknown Event’, it must be the case that nobody makes it back from their expedition alive – since otherwise they’d have told someone what happened, and the Event would no longer be Unknown. Luckily, [spoilers].

From the 2005 film *Proof*, in which Gwyneth Paltrow plays a mathematician (and also Jake Gyllenhall plays a mathematician, and Sir Anthony Hopkins plays a mathematician). **Catherine** (Paltrow)’s ageing father struggles to continue doing maths due to his degenerating mental state. She claims that among the many books of mathematical nonsense he’s generating, the one which contains a real, exciting and groundbreaking proof (of an unspecified mathematical conjecture, heavily implied to be the Riemann Hypothesis) was actually hers, and hilarity ensues. The film also implies that all mathematicians do loads of drugs all the time. Just like in real life.

This Japanese novel from 2003 features a number theorist, referred to only as ‘**The Professor**‘, who has suffered memory problems due to a car accident, and can only remember 80 minutes’ worth of time. He takes on a housekeeper, whose inquisitive son Root (so called because his head is flat, like a square root symbol) is invited to come to the house in the evenings, and together they learn about the beauty of equations.

A mathematical genius from Tom Stoppard’s 1993 play *Arcadia*, the 13-year old Thomasina works out chaos theory and the second law of thermodynamics by herself, and makes reference to such concepts as entropy, iterated equations and the deterministic universe. The play is set in two different time periods, and does not shy away from covering complex topics from maths and science, including chaos theory which is a main theme of the play.

2008 British film *The Oxford Murders*, based on an Argentine novel, stars John Hurt as Oxford mathematics professor **Arthur Seldom**. A strange series of murders occurs involving his friends, and a student played by Elijah Wood finds himself drawn into the mystery as events unfold. According to Wikipedia, Seldom’s research is in Logical Series, which is an entirely made up type of maths, but during the film they mention concepts such as “Wittgenstein’s rule-following paradox, Heisenberg’s Principle of Uncertainty, Gödel’s Theorem, circles, the Vesica Piscis, […] Fermat’s Last Theorem and its proof by Professor Wiles, the Taniyama conjecture, the tetraktys and the Pythagoreans” – although Fermat’s Last Theorem is called Bormat’s last theorem, and Wiles is called Wilkes. Nice.

From Neal Stephenson’s *Cryptonomicon*, a 1999 novel which, like Tom Stoppard’s *Arcadia*, is set in two different time periods – this time, WWII-era Bletchley Park, and the late 1990s fictional Sultanate of Kinakuta. In both settings, mathematicians work on code-breaking: one set striving to crack the Enigma and win the war, and the other working on modern-day cryptalgorithms for internet banking and data storage. The book doesn’t shy away from technical descriptions of the work, including prime numbers and modular arithmetic. **Waterhouse** is a US Navy codebreaker and mathematical genius, and his grandson Randy is present in the modern-day world.

From the 1971 psychological thriller *Straw Dogs*, which was banned on its first release due to extremely violent and brutal scenes throughout the film. Mathematician **David Sumner**, played by Dustin Hoffman, holidays in Cornwall with his wife, where characters from her past (horrendous understatement warning) cause trouble and events lead to Sumner behaving in a very unmathematical way. Not for kids. Or anyone probably.

**Chen Sung Yau** from *A Very Peculiar Practice* (suggested by @jamesbsumner) – this BBC comedy-drama series from the 1980s featured Peter Davidson as a doctor in a university medical centre. His flatmate, Chen Sung Yau, was a mathematician.

**Deep Thought** from *The Hitchhiker’s Guide to the Galaxy* (suggested by @kitkilgour) – not technically a mathematician since this giant computing machine is not human, but in the words of Kit, it “took its time, caused interest and gave an ‘accurate’ answer that was completely useless”. Sounds like a mathematician.

**Felix Rayman** (suggested by @madeleines) – from the 1980 sci-fi novel *White Light*, which explores the concept of infinity and the continuum hypothesis, and features cameos from Georg Cantor and Albert Einstein. Felix is a maths teacher who experiments with lucid dreaming and finds himself travelling to a magical place called Cimon, where they stay at Hilbert’s infinite hotel.

**Trillian** from Hitchhiker’s Guide to the Galaxy (suggested by @rockhyrax and @peterrowlett) – one of the group of adventurers Arthur Dent finds himself in the company of, Trillian (originally named Tricia McMillan, but she picked a spacier monicker for exploring the galaxy) is a ‘brilliant mathematician/astrophysicist’ – possibly the only one ever portrayed by Zooey Deschanel.

**Fred Burkle** (suggested by @peterrowlett) – from Joss Whedon’s *Buffy The Vampire Slayer* spin-off, *Angel*. (Wini)fred is a physicist and helps the team fight the forces of evil with equations. In later series, she heads up the science division of a large company, and any laughable suggestion that ‘scientist’ isn’t a specialism that one person can have is abandoned completely.

**Adric** (suggested by @usrbinprl) – from *Doctor Who*, Adric accompanied the fourth and fifth Doctors. Adric has a brilliant mathematical mind, and even wears a badge for ‘mathematical excellence’.

**Jane Grey** from *Action Science Theatre* (suggested @towelinmonk) – AST is 20-minute comedy science drama podcast, in the style of a radio play, that my friend Brian does. I’m sad to say I haven’t listened to it, but apparently it features a mathematician called Jane Grey, and maybe now I will.

**Captain Picard** (suggested by @peterrowlett) – Placing him one step closer to ‘greatest human of all time’, *Star Trek: The Next Generation*‘s Jean-Luc apparently dabbles in a bit of number theory when he’s not busy captaining a starship or being well-loved by everyone. Watch a video clip of him talking about Fermat’s Last Theorem.

**Mr Spock** (suggested by @sparkalisha) – of course, Picard’s not the only Starfleet crew member who’s mathematically inclined. As well as his constant quest for logic, Spock is often heard to quote the probability of extremely unlikely events (which never stopped Kirk from proceeding anyway, despite the odds). For a proper run-down of the maths in *Star Trek: TOS*, James Grime can sort you out.

**The camel in Terry Pratchett’s Pyramids** (suggested by @ianrobinson) – from the Discworld series, a wonderful fantasy/parody/social commentary series of novels by Terry Pratchett. In the seventh book, Pyramids, a camel (whose name is too rude to mention here) is described as “the greatest mathematician on the disc”, although it’s not clear if he’ll ever get the opportunity to show this, or if he did whether he’d actually be bothered to do so.

**“The Guy from Numberwang”** (suggested by @RDWhelan) – possibly a joke suggestion, but if you haven’t yet seen comedy duo Mitchell and Webb’s take on modern TV gameshows, you should take a look at some clips of it on YouTube, or buy their DVDs. That’s numberwang!

**D-503 from the novel We** (suggested by @liverbubble) – this Russian sci-fi novel is set in a futuristic world where everything’s made of glass, in which humans are numbered instead of named – including spaceship building engineer D-503 (who’s the central character). Having not read the novel, I can’t comment on his maths credentials, but I do like a good bit of dystopian sci-fi.

**The Mathemagician** (suggested by @danhett) – from *The Phantom Tollbooth*, a 1961 children’s novel by Norton Juster, adapted into a film in 1970. The twin kingdoms of Dictionopolis (ruled by King Azaz) and Digitopolis (ruled by his brother, The Mathemagician) continue the age-old argument as to which is better, letters or numbers.

**Mr Peabody** (suggested by @hankmcljr) – originally a character in the Rocky/Bullwinkle-based children’s cartoon series, Mr Peabody is a highly intelligent beagle, who adopts a human child to keep him company and together they travel in time. Made more well-known by the 2014 movie, although Mr Peabody is more of a generalist than a mathematician specifically.

**The Number Devil **(suggested by @sellathechemist) – this 1997 novel by Hans Enzenberger features a young boy who is guided through his worries about mathematics by The Number Devil, who visits him in his sleep and explains mathematical concepts using simple analogies. I’m confused. Doesn’t that happen to everyone? That’s how I learned maths.

**El Nombre **(from Facebook): this anthropomorphic Mexican gerbil, who appeared in sketches during BBC Schools’ NumberTime, was always on hand whenever counting or numbers were needed, and would show everyone how to draw the different shapes of numbers by drawing them in the sand. The clips are still available on YouTube, in case you’re not sure.

**Dexter** (suggested by @sparkalisha) – not to be confused with serial killer Dexter Morgan from the HBO series Dexter (he is a different kind of scientist), Dexter from Dexter’s Laboratory is a boy-genius scientist, and since all science is maths, presumably also a maths genius. If only he could keep his annoying sister from finding her way into his lab! Hilarity ensues.

**Count Von Count** (suggested by @tombutton) – from Sesame Street, this mathematical muppet delights in counting loudly the number of things that there are, then laughing maniacally. Specialism: set theory. Apparently he was a guest on BBCR4’s More or Less in 2009.

**Udo of Aachen** (suggested by @watfordpete) – introduced in an April fool’s hoax in 1999, Udo is a fictional monk from the 13th century, created by author Ray Girvan. Udo is credited with the discovery of the Mandelbrot Set, centuries before Benoit Mandelbrot.

**Fictional incarnations of Ada Lovelace** (suggested by @jamesbsumner) – her status as a singularly well-known female mathematician of the era means she crops up in a lot of period fiction, including steampunk novel *The Difference Engine*, which I’ve read and is good.

**Nicolas Bourbaki** (suggested by @sparksmaths and @jamesmoosh) – this French mathematician set out to reformulate mathematics in the 20th century, using a grounding of set theory. Only he didn’t actually exist, and was the pseudonym of a group of mathematicians including Henri Cartan, Jean Coulomb, André Weil, Jean-Pierre Serre and Alexandre Grothendieck, among many others. Bourbaki is credited with the invention of the empty set symbol ($\emptyset$), the terms ‘injective’, ‘bijective’ and ‘surjective’, and the ‘dangerous bend‘ symbol (which I bet you’d never heard of either).

**Pythagoras** (suggested by @kesmathematics and @casmilus) – while there may well have existed a mathematician and philosopher called Pythagoras of Samos, it’s been suggested that many of the mathematical discoveries attributed to him were in fact discovered by his followers, and so like Bourbaki he was a collection of people working under the one name. All references to Pythagoras came from the accounts of his followers, suggesting they made him up – also, he was variously suggested to be the son of the god Apollo, and to have a golden thigh. Sounds legit, right?