# algebra

Groups have become a core part of the language of modern mathematics and theoretical physics. On this page, find out how groups can help describe roots of polynomials, holes on a surface, and even the laws of physics!

Group theory is the mathematics of symmetry and structure. On this page, find out what a group is and how to think about them.

Creep up on polynomials with this quick introduction.
What is group theory and why is it such an exciting area of maths? Two experts explain.
Having trouble with algebra? Then try these visual proofs of two well-known algebraic identities.
How to derive the famous quadratic formula from pictures, just like the Babylonians did.
It's International Year of Astronomy and all eyes are on Galileo Galilei, whose astronomical observations 400 years ago revolutionised our understanding of the Universe. But few people know that Galileo wasn't the first to build a telescope and turn it on the stars. That honour falls to a little-known mathematician called Thomas Harriot, who excelled in many other ways too. Anna Faherty takes us on a tour of his work.

### The Plus anniversary year — A word from the editors

In the fourth and final part of our series celebrating 300 years since Leonhard Euler's birth, we let Euler speak for himself. Chris Sangwin takes us through excerpts of Euler's algebra text book and finds that modern teaching could have something to learn from Euler's methods.
Winner of the general public category. Enormous is the right word: this theorem's proof spans over 10,000 pages in 500 journal articles and no-one today understands all its details. So what does the theorem say? Richard Elwes has a short and sweet introduction.
Groups are some of the most fundamental objects in maths. Take a system of interacting objects and strip it to the bone to see what makes it tick, and very often you're faced with a group. Colva Roney-Dougal takes us into their abstract world and puzzles over a game of Solitaire.
A brief look at Emmy Noether's challenging journey to become one of the twentieth century's great mathematicians.