### 15th June 2017 - Leonard Hardimain

#### Volume

There has recently been much interest in the mathematical community with the concept of volume (see, for example, [1]). To capitalise on this hot new trend I shall present the difficulties that arise when one attempts to define this tricky concept. As the subject matter is highly advanced I shall first discuss the relatively simpler concept of area.

Prerequisites: Length.

[1] Euclid, Elements Book 11, Elements, circa 300 BC.

### 29th June 2017 - Cameron Smith

#### A practical guide to party tricks that *really* get you noticed (in a weird way!)

Have you ever wondered how to find the decimal represention of 1/19 without actually dividing by 19? Or what about multplying 97 by 92 in less than five seconds, without a calculator or a pen and paper? Do you want to be able to square 85 in your head with little more than a small amount of thought? If you answered yes to any of these questions then PSSS will be right up your street this week. If not then why not come along anyway, you'll get to watch a rather under-prepared postgrad doing live arithmetic, which is always fun!

Introducing Vedic mathematics. Re-discovered in the 1910's by Sri Bharati Krsna Tirthaji and based around 16 sutras (formulae) and 15 sub-sutras (corollaries), Vedic mathematics aims at making maths more coherent. Why do long multiplication and addition backwards when you can do it forwards in far less time? I will introduce several different techniques in the hope that at the next party, I'm not the only one bringing the mood down!

### 27th July 2017 - Pablo Vinuesa

#### Logic puzzles

In this talk I aim to introduce the audience to some logic problems in mathematics. One of these is, in fact, called "the hardest logic puzzle ever". This is a famous problem in logic consisting of being able to determine the identity of three gods, one who tells the truth, another who lies and the last one who speaks the truth or lies randomly.

### 10th August 2017 - Jack Betteridge

#### Why you should never use a computer to do mathematics

Computers seem to have become commonplace in almost every aspect of our lives, so it is unsurprising that they have also entered the world of mathematics too. Beyond just LaTeX documents and scanned in textbooks, computers are actually performing calculations. But, to what extent are these calculations even correct?

In this talk I will look at how a computer represents and stores numbers that are used for calculations, and, by means of examples, show exactly what can go wrong when a computer does the maths. There will also be a friendly competition, a computer versus the audience, so be sure to bring either a computer, a hand calculator or a brain containing some basic analysis skills.

### 24th August 2017 - Leonard Hardiman

#### You Can't be Serialist!

When G.d. Mathieu and I were both 24 we composed a piano piece entitled 'Ile de Feu 3'. It is intended as a companion piece to the earlier work 'Ile de Feu 2' which was composed by G.d. Mathieu when he was 12 and Olivier Messiaen.

I will present our work and explain our musical process.