This is the **158th** **Carnival of Mathematics**, a monthly round-up of interesting maths bits from across the internet. Convention dictates that I now therefore specify some interesting facts about the number 158. Unfortunately I am writing this on a train with no internet access, which will make fulfilling this obligation more than usually challenging.

# You're reading: Blackboard Bold

### I’ve written some stuff for the HLF Spektrum blog

Since blogging for the Heidelberg Laureate Forum last September, I’ve now started writing regular posts for their all-year-round blog, which is hosted at Spektrum SciLogs.

My first two posts are:

- a writeup of Robert Langlands’ work that won him this year’s Abel prize
- a post expanding on the recent chromatic number result by Aubrey de Grey

Keep an eye on the Spektrum blog, and the Aperiodical Twitter feed for news of further posts!

### Review – A Mind At Play: How Claude Shannon Invented the Information Age, by Jimmy Soni and Rob Goodman

For a while now I’ve been fascinated by the story of Claude Shannon, the pioneer of information theory and the originator of many fundamental concepts now used in all modern manipulation and transmission of data. Being sent a copy of this biography to review was a great chance to find out more about his work and life.

**A Mind At Play: How Claude Shannon Invented the Information Age
**

**Jimmy Soni and Rob Goodman**

The authors, who describe themselves as biographers and writers foremost, have taught themselves the mathematics they need to explain Shannon’s work, and weave in some excellent and succinct explanations of the concepts amongst a fascinating human story. From his early years as an enthusiastic maker and tinkerer, through his various university courses and his placement at Bell Labs, to his later years at MIT and retirement, Shannon’s life is chronicled in detail, with a spread of well-chosen photographs to accompany the story.

Claude Shannon is described as the father of information theory – his seminal 1948 paper outlined concepts including the fundamental nature of binary numbers (coining the word ‘bit’, a binary digit), information density, communication channels, and the theoretical Shannon Limit of how quickly digital information can theoretically be transmitted in a noisy channel. These ideas predated even simple computing machines, and Shannon’s work was perfectly timed to provide a foundation for those creating early computers.

The story gives a real sense of how Shannon was well placed to create the mathematics he did – with a sharp intellect that was torn between his love of abstract mathematical theory and his fondness for hands-on inventing and engineering, he had just the right mindset to see what communication theory would become and how it could be made rigorous in a mathematical framework.

It’s also fascinating to learn about Shannon’s other passions in life – nothing he did before or since comes close to the major impact his work on information theory had, but it was far from his only passion. Other areas of mathematics and engineering, as well as pastimes including juggling, stock market predictions, and building robots all fell to his mighty intellect and he brought huge joy to the people around him with his stories and ideas.

The book is well written and lovingly put together (and has a frankly beautiful cover in the hardback edition). It was enjoyable to read, and full of interesting facts and stories. I didn’t realise until reading this book that a wooden box I have at home, which has a switch on top that when flipped, engages a robotic arm that pops out and flips the switch back again, is a modern incarnation of an invention of Shannon’s – he called it ‘the ultimate machine’, one which switches itself off. Knowing this was his original creation, and the joy I find in it, gives me a real sense of connection to this brilliant mathematician whose work changed the world for all of us.

A Mind At Play: How Claude Shannon Invented the Information Age by Jimmy Soni and Rob Goodman is published by Simon and Schuster.

### πkm run challenge – completed

As a final update, I’ve now finished my πkm running quest. I’m very tired now! Thanks to everyone who has donated at pikm.run, spread the word about it, come running with me or otherwise facilitated this.

Here’s the final set of photos and video clips from the last week, and for the data fiends among you, a sneaky look at my spreadsheet of runs. With a graph, as requested by Hannah Fry.

### πkm running challenge: 21-day round up

I’m still going! Two-thirds of the way through my epic running binge, and I’ve managed to keep it up every day so far. Since my last round-up on 7th, I’ve run another πkm each day, and my fundraising total is now at 22%, which is over £700 (and if you didn’t notice, that sentence just contained ’22’, ‘over’ and ‘7’).

If I can make it to £1000 before the end of the month, I’ll be pretty pleased! Donate at pikm.run, or see below for my daily sweaty photos/videos/instagram posts.

### πkm Running Challenge: 7-day update

This month I'm doing a completely irrational sponsored run for Sport Relief, aiming to raise £100π by running πkm per day, every day in March. I'm one week in, and here's the story so far.

### Prime Time

We spotted this photograph of a letter to The Telegraph, shared by Card Colm on Twitter earlier in the year. It’s exactly the kind of mathematical claim we like to enjoy verifying, so we thought we’d dig in.