## Articles

**Phil Wilson**looks at

*constructivist mathematics*, which holds that some things are neither true, nor false, nor anything in between.

**Angus Brown**looks at one of these, a simple model for option pricing, and explains how it takes us on the road to the famous Black-Scholes equation of financial mathematics, which won its discoverers the 1997 Nobel Prize in Economics.

**John Billingham**investigates and saves the national grid in the process.

**Lewis Dartnell**looks at some stunning examples.

**Peter Markowich**is a mathematician who likes to take pictures. At first his two interests seemed completely separate to him, but then he realised that behind every picture there is a mathematical story to tell.

*Plus*went to see him to find out more, and ended up with a pictorial introduction to partial differential equations.

**Liz Newton**finds that having a small brain doesn't stop you doing great things.

**Neil Pieprzak**tells the fascinating story of Andrew Wiles who, with intense devotion and in secret, proved a deceptively simple-looking conjecture that had defeated mathematicians for almost 400 years.