City University London





LIST OF THIRD YEAR PROJECTS FOR THE ACADEMIC YEAR 2006/07
Project 1:  Is there a fair voting system?

There are a wide variety of different voting systems in use around the world. Each has been designed with a different purpose in mind, but we would like to believe that most of them are probably fair. But is it possible to prove that this is the case?

This project will give an introduction to some of the various different voting systems that exist, consider what we might require from a fair voting system, and explain why our quest for a fair voting system may be doomed to failure. Part of this will be based on work of
Kenneth Arrow (a Nobel prizewinner in Economics).
Project 2:  A Mathematical model of the Severn Barrage

Tidal estuaries offer a means of extracting clean energy by using the movement of water to power large turbines. Such a scheme was originally proposed for the Severn estuary as long ago as 1925 and is now once again under serious consideration. Tidal power is already used successfully to generate electricity in many other parts of the world. The aim of this project is to develop a simple mathematical model of such a system. This will involve some inviscid fluid dynamics leading to a mathematical problem requiring the solution of the relevant governing equation and boundary conditions. The solution is likely to involve some analytical work together with some algebraic computations. The main objectives are to determine how the flow depends on the geometry of the system and to discuss the results in the context of practical applications.
Project 3:  The Science of the Ethics of Finance:
Islamic Finance and other Ethical issues treated Mathematically

Most financial instruments arising in 'western style' finance may be understood mathematically. Many such instruments are  designed to work without ethical constraints, or consideration of their social implications. On the other hand some financiers choose to apply ethical and related constraints to their financial instruments. A prime example is the instruments of Islamic finance (although there are plenty of others). These instruments still operate  in a framework which is prescribed by Mathematical considerations, but they are also constrained by (say) consideration of Sharia law. The purpose of this project is to provide a mathematical, logical, semantic analysis of such instruments. The first aim is simply to explain the instruments mathematically,  and analyse their relationship with the ethical constraints which motivated them. The second aim is to use this machinery to  discuss their fitness for purpose, and perhaps to consider alternatives (and the reasons why conventional instruments may not be acceptable). This is a rigorous project - following a strict definition based construction of components, with logic based arguments. It is anticipated that some of these arguments will use mathematical language, and others logical argument in English. As such a good mastery of English is (unfortunately) a prerequisite.
Project 4:  The mathematics of juggling

What kind of mathematics can be used to describe juggling? And what kinds of questions can it answer? This project will be an introduction to Combinatorics -- a branch of mathematics used in many areas in Computers Science, Statistics, and general Mathematics -- concentrating on juggling as a source of particularly simple and easy to understand examples.  
Project 5:  Simple models of random processes

A core model in the simulation of processes such as the evolution of stock market prices is that of a random walk. The random walk on a line (measuring, say, the cost of a stock over time)  is closely related to the combinatorics of the binomial theorem and Pascal's triangle. There are a number of ways of generalising this to widen the potential for applications. For example we might replace the walk on the line by a walk on a more interesting shape. The idea of this project is to investigate this problem by applying and modifying a number of techniques already broadly familiar from the undergraduate syllabus.

The project is suitable for up to 3 or 4 students, who might collaborate to some extent in the scientific investigation, but who would be required to produce independent project reports.
Project 6: Non-linear stock market price dynamics

Stock market prices are strongly influenced by two classes of investors, so-called fundamental value investors and so-called trend followers. Recently (2001) a simple two-dimensional model has been proposed which simulates the influence of such type of investors on prices in the stock market in a non-linear fashion. One of the two dynamical variables is taken to be the logarithm of the ratio of the observed price over the fundamental price. The other variable is the market trend. The system is known to possess an unstable fixed point when the observed price equals the fundamental one and the market trend is zero, that is when the stock "does not know"  in which direction to develop. The purpose of the project is to study this model in some detail depending on various market parameters.
Project 7: Graphs and maps

Given a map of an area divided into regions, how many colours are needed so that no two adjacent regions have the same colour? Can you redraw the map so that each region is replaced by a square, without altering which regions are adjacent? Can you visit every region exactly once without retracing your steps?

These are examples of problems that can be solved using Graph Theory, an area of mathematics with many practical applications (for example in computing and telecommunications). This project will provide an introduction to the methods used to solve such problems.
Project 8:  Applications of physics to economics and finance:
Money, wealth and the stock market


Many problems arising in the context of economics and finance can be analysed by using methods and concepts from physics. For instance, by analogy with energy, the equilibrium probability distribution of money must follow the exponential Boltzmann-Gibbs law characterized by a temperature equal to the average amount of money per economic agent. Based on this observation one can construct a "thermal machine" which extracts a monetary profit between two economic systems with different temperatures. With such analogies one can investigate stock market fluctuations, probability distributions of income and many other problems in economics and finance. The purpose of the project is to test such ideas which were presented in a recent (2003) essay.
Project 9: Symmetry and Groups

The notion of symmetry is fundamental in Sciences, for instance in Chemistry the symmetries of a molecule determine some of its properties. The aim of these projects is to study the symmetries of 2 dimensional figures, like tilings or wallpapers (think for example of some of the patterns designed by Escher) and some 3-dimensional figures (for example some molecules). The mathematical concept underlying these symmetries is the notion of a "group". This will be used to classify symmetry types of figures.
Project 10: Quantum finance

Most financial models which simulate market behaviour are of stochastic type. In such models coherent effects, such as the influence of the trade of securities on the price distribution of the next trade are not captured. Recently (2003) it has been proposed to use a quantum theoretical description, which can take such effects naturally into account. The idea of the project is to describe such a quantum theoretical model. Key ideas are for instance that all possible realizations of investors holding securities are taken as a basis for a Hilbert space. Linear operators acting in this space describe basic financial transactions, such as cash transfer and buying and selling of securities. Simple Hamiltonians can be used to describe the temporal evolution of the market. This project can accommodate 1-3 students.
Project 11: The geometry of animation 

Shrek is an oscar winning animated film which was "shot" by creating a virtual world in a computer and then rendering scenes from this world entirely in software. The rules for this world were: 1. obey the director; 2. obey a few rules of ordinary physics, and 3. obey the rules of 3D geometry (such as those studied in the Geometry and Vectors course). The idea of this project is to exercise or reinforce our understanding of this applicable geometry by making a "mini-Shrek" (perhaps 5 seconds of animation). Step 1 is to create a virtual geometrical world consisting, say, of a single human hand with water (perhaps rain) running down it and collecting in a droplet at one fingertip. Here "create" means to give a geometrical description of the shapes and positions of objects at each of a number of moments in time. This might be done using one of the standard computer languages for describing geometry (these languages are easy to learn, and no prior knowledge would be required). Step 2 is to "film" this action (i.e. to choose where to view it from, how to move the "camera" etc.). Step 3 is to render this scene into a format suitable for viewing on your online CV/web page.

THIS PROJECT IS SUITABLE FOR UP TO 4 PEOPLE WHO WOULD PRODUCE SEPARATE SOLUTIONS TO STEPS 1 AND 2, BUT COULD COOPERATE ON THE UNDERLYING THEORY AND ON STEP 3.
Project 12:  Quantum computing

Computer chips are made smaller and smaller and one naturally imagines that eventually a limit is reached in this process once the atomic scale is reached and quantum mechanical effects become relevant. However, at this scale new possibilities emerge due to the occurrence of a phenomenon called entanglement, which is specific to quantum mechanics and shall be explored in this project. In fact P. Shor showed in 1995 that one can exploit this characteristic of quantum mechanics and design computers which are far more efficient than classical computers. The idea of this project is to give an account of the general principles and concepts of quantum computing, in particular on Shor's algorithm. By comparing the amount of additions and multiplications needed in a classical computer with the number of quantum gates needed, the potential power of a quantum computer will become apparent.
Project 13:  Solving unsolvable problems

For most problems in theoretical physics or applied mathematics analytical solutions are not known. Often this is only a matter of consistent investigations, but many times the situation is hopeless as a proper mathematical framework does not exist. Non-linear integral equations are examples for this, as there is no systematic solution procedure developed for them. With the advance of computer technology more and more problems allow for a numerical treatment. The idea of this project is to write ashort computing program to solve a set of coupled non-linear integral equations which play an important role in the theory of quantum integrable models. The problem can be treated without reference to its background in physics, but according to preferences one can also learn about the contextin physics where they occur. This project can accommodate 1-3 students.
Project 14: Dimensions and Fractals: measuring complexity

The notion of dimension we are mostly familiar with goes back to Euclid's definitions of point, line, surface and solid and to Descartes coordinate geometry. This is the notion of topological dimension, which tells us that points have dimension 0, lines have dimension 1, the interior of a square has dimension 2 and that of a sphere 3 etc. However this concept of dimension can not always be used, for instance if we imagine a curve such that it covers all the 2-dimensional plane (as for example the famous Peano curves) and try to answer the question of what its dimension is we would not know whether to say 1 or 2. Precisely fractals are objects for which a similar problem arises and a more suitable definition of dimension (fractal dimension) need to be introduced. Examples of those are the so-called Hausdorff dimension (1919) or the box-counting dimension, which for most examples coincide. It turns out that we can find many systems for which the fractal dimension and topological dimension do not coincide. In fact, a definition of fractal introduced by B. Mandelbrot is that of a set whose dimension is strictly larger than its topological dimension. Nonetheless, the essential property of a fractal is that it has and infinitely complex structure which extends over all length scales. It is also a mathematical feature of fractals that they are often generated by recursive equations. That is the case of two of the most widely studied groups of fractals known: the Julia sets and the Mandelbrot sets.

Fractals are very interesting objects from a mathematical point of view but they also resemble very often real structures or patterns we find in nature (like tree leaves, snow flakes, shells or the color patterns of certain animals). That makes them all the more fascinating!

In this project I would like the students to write an essay about fractals: how did they first appear?, how has their study developed?, what are their main characteristics from the mathematical point of view? etc. Several students could do this project, in which case each of them should concentrate (after a general introduction) on a different kind of fractal and describe the fractal of his/her choice in more detail. It would be very interesting if the students could actually generate some fractals numerically and therefore understand better how they come about. 
Project 15: The theory of special relativity

The theory of special relativity was proposed by Albert Einstein in 1905 in his paper entitled "On the Electrodynamics of Moving Bodies". About 300 years earlier, Galileo had already stated that all uniform motion was relative, and that there was no absolute state of rest. In other words whether an object moves or not depends on the relative position of the observer with respect to the observed object. Einstein's theory  is based on two fundamental axioms:
  • Galileo's relativity principle: No experiment can mesure in an unambiguous way the velocity of an inertial observer.
  • The universality of the speed of light: The speed of light is a universal constant, which is independent of the relative velocity between the source emiting light and the observer.  In addtion, no material object can travel faster than light.
As we have said, the first axiom was already quite old, but the second one implied a completely new understanding of the way space and time are tied together and, in particular, contradicted the Newtonian notions of absolute space and time. It had various a priori "surprising" consequences that have since been verified experimentally: the equivalence of matter and energy expressed in the famous equation E=mc², where c is the speed of light, the fact that time and space become relative to the observer and that on the contrary the speed of light becomes an absolute quantity, independent of  the velocity of the observer himself.

The aim of this project is that the student or students write down an introduction to the theory of special relativity, emphasizing the mathematical aspects of the latter and explaining how the two main axioms above imply the relativity of space and time.  The project should also describe the main differences with respect to Galileo's theory and show how the theory of special relativity is consistent with the latter for velocities much smaller than the velocity of light.
Project 16: Neural networks

The description of nature is usually carried out by means of some model or theory based on various mathematical equations. However, often such model is not at hand or the situation one would like to describe is simply too complex. Neural networks are designed to overcome this deficiency and have the ability to derive meaning from very complicated or even imprecise data. They can be used to extract patterns and detect trends that are too complex to be noticed by either humans or other computer techniques. There are different kinds of neural networks, such as biological neural networks, as for instance the human brain or parts of it and also artificial neural networks originally referred to electrical, mechanical or computational simulations or models of biological neural networks. Meanwhile the field has expanded so much that some applications do not clearly resemble any longer an existing biological counterpart. The adaptability of neural networks is so large that their applications nowadays range from fundamental subjects as biology and physics even to banking, finance, insurance, marketing, manufacturing, etc. The purpose of the project is to provide an introduction to neural networks, give their brief history, investigate simple network architecture and consider some realistic applications. Students are encouraged to write a simple program for some neural network, such as for instance for pattern recognition or similar. The programs could written in MATLAB, Mathematica or Maple or similar languages. This project can accommodate 1-4 students.
Project 17: Knot theory

Take two pieces of strings and tie a knot in each. Although they may look very different, is there a way to determine whether the two knots are in fact the same? This is one of the fundamental problems in Knot Theory, and these projects will investigate the various methods that have been introduced to try to solve it. The study of knots is a relatively new subject, with applications in various areas of Biology, Chemistry and Physics. 

In these projects the students will each explore a different aspect of the subject. The goal is to write a clear but rigorous introduction to the chosen topic, and to apply the results obtained to a variety of examples.
Project 18: Cryptology

Cryptology is the science concerned with communications in secure and usually secret form. The term cryptology is derived from the Greek kryptós (hidden) and lógos (word). Security is "guaranteed" to legitimate users, the transmitter and the receiver, being able to transform information into a cipher by virtue of a key, i.e. a piece of information known only to them. Although the cipher is inscrutable and often unforgeable to anyone without this secret key, the authorized receiver can either decrypt the cipher to recover the hidden information or verify that it was sent in all likelihood by someone possessing the key. Until recently this was mainly important to military circles, but in the computer age the applications of cryptology become more and more widespread, as for instance in on-line business transactions. Meanwhile cryptology has developed into an important branch of mathematics and the idea of the project is to write an account on cryptology and explain some of  its main concepts and techniques. This project can accommodate 1-4 students.
Project 19: The Goldbach conjecture

In 1742 Christian Goldbach proposed in a letter to Leonard Euler the following conjecture: "Every integer greater than 2 can be written as the sum of three primes", where he considers one as a prime number. Nowadays the conjecture is usually formulated as: "Every even number greater than 2 can be written as the sum of two primes". Even though this conjecture has been checked by computers up to 2 x 10^17, a rigorous proof is still not known. Between 2000 and 2002 a prize of 1.000.000 $ was offered for the proof, but it remained unclaimed. Goldbach's conjecture remains one of the most challenging unsolved mathematical problems. The idea of this project is to give an account of some of the attempts made so far and understand their limitations and to design a computer program which verifies the conjecture up to X, where X is the challenge. This project can accommodate 1-3 students.
Project 20: The butterfly effect: what is chaos?

In mathematics and physics chaos theory is understood as the study of certain non-linear dynamical systems which under particular conditions exhibit the phenomenon known as chaos. The latter is most famously characterized by the extreme sensitivity of these systems (equations) to the initial conditions. Many examples of such systems appear in the context of physics: the atmosphere, the solar system, plate tectonics, turbulence in fluids but also in other domains such as economics or populations growth. Some of the best known systems which exhibit chaos are:

The Lorenz model: this is one the most interesting and more widely studied systems of equations which exhibit chaos. The equations involved are three coupled first-order non-linear differential equations which describe in a simplified way the convection rolls arising in the atmosphere

               ẋ(t)=a (y(t) - x(t)),      ẏ(t)= x(t)(r-z(t))-y(t)     and     ż(t)= x(t)y(t)-b z(t),

with x(t) representing the intensity of the convection and y(t), z(t) related to the horizontal and  vertical temperature distributions. a, r, b are positive constants. In his original work, Lorenz took a=10 and b=8/3 and varied r. He found chaos for r=28. For these values of the constants, a three dimensional plot of the variables {x(t),y(t),z(t)} for different values of t yields the famous Lorenz strange attractor, characterized by its shape, similar to the wings of a butterfly.

The logistic map: Another system of equations which sometimes exhibits chaotic behaviour is the so-called logistic equation. The latter describes a discrete one-dimensional dynamical system characterized by the equation:
                                                           x(n+1)= a x(n) (1-x(n)),

where n=0,1,2 ..., a is a constant parameter and x(n) takes values between 0 and 1. This equation was originally used  as a simple demographic model, with x(n) representing the amount of individuals of a certain population at year n. For values of a>3.57 the system exhibits chaotic behaviour, which in particular means the values of x(n) for n very large are extremely sensitive to the initial value x(0). Before reaching the chaos regime there is a region where another peculiar phenomenon occurs namely that of bifurcation.

The aim of this project will be that the students familiarize themselves with the most basic aspects of the theory of chaos and write an introduction about the subject. Then each student should concentrate on one of the models described above (or other examples)  and answer if possible questions such as: for which values of the parameters does chaos emerge? What are the characteristic of the solutions which lead us to conclude the existence of chaos? Are there regions were stable solutions exist (fixed points)? How can be determine those? how do the solutions of our equations approach these fixed points? What is an attractor? What is a bifurcation? etc. It would be very instructive if the students could use some computer program (such as MATHEMATICA or EXCEL) in order to investigate the equations numerically.
Project 21: The shape of the world

How do we know the world is round? Is it possible that we live on a big donut rather than a sphere? Of course, if we travel in space then we can prove that the surface of the Earth is a sphere but people knew it long before travelling into space. What was the evidence?

These projects will investigate different mathematical methods to tell surfaces apart and study their properties.

The Poincaré conjecture is concerned with the same problem in 3 dimensions. Last August, Grigori Perelmann was awarded (but declined) the Fields Medal for his proof of this conjecture.
Project 22: The millennium problems

In May of the year 2000, in a highly publicized meeting in Paris, the Clay Mathematics Institute announced that seven $1 million prizes were being offered for the solution of each of seven unsolved mathematical problems. These problems had been chosen by an international comitee of mathematicians to be the most difficult and most important in the field today. The seven millennium problems are:
  1. The Riemann Hypothesis
  2. Yang-Mills theory and the Mass Gap Hypothesis
  3. The P versus MP Problem
  4. The Navier-Stokes equation
  5. The Poincaré conjecture (recently solved by G. Perelmann!)
  6. The Birch and Swinnerton-Dyer conjecture
  7. The Hodge Conjecture
You can find more information about them in the Clay Mathematics Institute website www.claymath.org. A very nice and simple introducction to each of the problems is also given in the book: The millennium problems by Keith Devlin. The idea of this project would be that you write a report about each (or some) of this problems trying to answer questions such as: what is the problem about? why do you think it is so difficult to solve it? do you know of any attempts to solve it? why were they not successful?
Project 23: How to become a millionaire by solving  a mathematics problem

Various mathematical problems are around for a rather long time without having been solved to this day. In order to stimulate the interest of Mathematicians several prizes have been announced for their successful solution. For instance, the Clay Mathematics Institute has named seven prize problems which will be awarded with 1000000$. One such problem is for instance the Poincaré conjecture: If one stretches a rubber band around the surface of an apple, then one can shrink it down to a point by moving it slowly, without tearing it and without allowing it to leave the surface. On the other hand, if one imagines that the same rubber band has somehow been stretched in the appropriate direction around a doughnut, then there is no way of shrinking it to a point without breaking either the rubber band or the doughnut. One says the surface of the apple is "simply connected," but that the surface of the doughnut is not. Poincaré, almost a hundred years ago, knew that a two dimensional sphere is essentially characterized by this property of simple connectivity, and asked the corresponding question for the three dimensional sphere. Poincaré conjecture was recently solved by Grisha Perelmann from St. Petersburg. He refused to accept the prize money as well as the fields medal, which is the equivalent of the Nobel prize in Mathematics. The idea of the project is to describe the Mathematics behind these problems and possibly indicate to what extend progress has been made to solve them. You may of course try to solve a problem and become a millionaire.
Project 24: Number theory applied to cryptography

Number theory is that branch of mathematics concerned with the properties of  integers. It contains many results and open problems that are easily  understood, even by non-mathematicians. More recently, the field has found  applications to practical problems, the most popular of which is  cryptography.

In this project we review the basic ideas of number theory that underpin several cryptographic protocols, with an emphasis on the Diffie-Hellman and  RSA methods.

Project 25: Brownian motion in Physics, Mathematics and Finance

Brownian motion is named after the biologist Rober Brown (1773–1858). While  examining pollen grains and the spores of mosses suspended in water under a  microscope, Brown observed minute particles in the pollen grains executing a jittery motion. He then observed the same motion in particles of dust, and in  other small particles suspended in liquids. Although he did not himself  provide a theory to explain the motion, the phenomenon is now known as Brownian motion in his honour.  Albert Einstein gave in 1905 a physical interpretation of Brownian motion that  helped establish the reality of atoms, which until then had been regarded as  theoretical speculation. More detailed theories followed Einstein's work, and  by now Brownian motion is an important branch of the mathematical theory of stochastic processes. In recent years, it has been found that Brownian motion  provides a rather good description of the fluctuations of financial markets, and has now become a fundamental object in all modern applications of mathematics to Finance. The goal of this project is to present a reasonably complete review of  Brownian motion as a stochastic process and of its various manifestations in the real world.
Project 26: Shadowgraphs in the ocean

One of the most important mechanisms for the mixing of salt in the oceans is by ``salt fingers''.  These fingers consist of tall, thin (about 3cm) plumes of water with a different heat and salinity to their surroundings.  One method that has been used to try and observe these in the oceans is the "shadowgraph technique": a beam of light is shone through a patch of water and the variations in the refractive index of the water caused by the heat and salt variations causes the parts of the beam to deviate.  These deviations are observed by projecting the beam onto a screen/camera.  The purpose of this project is to calculate the images that would be expected from the salt fingers using
analytical and numerical methods and to compare these results with the images that were recorded in the oceans.
Project 27: Wallpaper patterns and crystals

When you buy patterned wall paper you will find that the pattern repeats itself, both along the roll and across it. For big patterns the across roll pattern may  only be clear when it is hung. How many repeat patterns are there? For example, in some patterns it will not matter which way up you hang each strip (or even if you hang them horizontally!) while for others it does. Some look the same in mirrors, others don't. In this project you will determine rigorously the number of possible repeat patterns  for wall papers. This can then be extended to look at, say, not repeating patterns in wall paper or the structures of crystals.
Project 28:  The use of Laplace transform in ordinary differential equations

Many linear ordinary differential equations do not have explicit solutions. One way that we can examine the properties of the solutions is by using the method of Laplace transforms. This technique will be covered in X3 Mathematical Methods. It is a method that can sometimes reveal how a solution y(x) behaves, for example, for small values of x or as x goes to infinity.