# Page 3 model: When zombies attack

Run? Kill? Ask nicely? (Source: flickr.com/joelf)

Every issue we feature another great model on page 3 of our magazine. This issue it’s this:

\begin{align*}
S’ &= \Pi – \beta S Z – \delta S,\\
Z’ &= \beta S Z + \zeta R – \alpha S Z ,\\
R’ &= \delta S + \alpha S Z – \zeta R.

# Dear Dirichlet, Issue 01

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

### 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?

# 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

Blackboards

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.

# Top Ten: Mathematicians’ haircuts

This issue, Top Ten features the best haircuts held by mathematicians!

10. Rumour has it that judges’ wigs were inspired by Leonhard Euler’s hair.

9. Peter Dirichlet loves answering your letters and caring for his hair.

# £100 Prize Crossnumber, Issue 01

Our original £100 prize crossnumber is featured on pages 34 and 35 of Issue 01.

### Rules

• Although many of the clues have multiple answers, there is only one solution to the completed crossnumber. As usual, no numbers begin with 0.
• One randomly selected correct answer will win £100. Three randomly selected runners up will win a Chalkdust pen. The prizes have been provided by G-Research, researchers
of financial markets and investment ideas. Find out more at gresearch.co.uk.
• To enter, email crossnumber@chalkdustmagazine.com with the sum of the across clues by 22 July 2015. Only one entry per person will be accepted. Winners will be notified by email by 1 August 2015.
• Entry is now closed.