Cracking the Guess Who? board game

Does this person have ginger hair?
  Is this person a boy?
  Is she wearing a hat?
  Is your person Anita?

Maybe everyone has played Guess Who?: the board game where you try to guess which character your opponent has before they find out yours. For those who have never played Guess Who?, the game goes as follows: each player picks a card at random, on which will be drawn the face of a character. In turns, the two players ask each other yes/no questions to try and guess who their opponent has picked. A board with all the images of the characters initially standing up helps the player keep track of which ones have been eliminated along the way. Continue reading


Dear Dirichlet, Issue 01

Moonlighting agony uncle Professor Dirichlet answers your personal problems. Want the Prof’s help? Send your problems to

Dear Dirichlet,

This week’s problem sheet asks me to show that $\log(x) < x-1$ for all $x > 0$. To me this seems obviously true – a quick sketch backs it up as well. I think I’m supposed to use Taylor series or something but I’m not sure where to start. Can you help?

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What’s hot and what’s not, Issue 01

"A blackboard, for a mathematician, is an unrivalled way to communicate" - Cédric Villani, Fields Medallist 2010

“A blackboard, for a mathematician, is an unrivalled way to communicate” – Cédric Villani, Fields Medallist 2010


The mathematical equivalent of a Little Black Dress. Blackboards will never go out of style.

E-learning systems

In the immortal words of the Black Eyed Peas, interactive whiteboards are so two thousand and late.

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