School of Mathematics and Statistics

Mathematics and Statistics Colloquia

Colloquium

Contact

Dr Luke Morgan
Telephone (+61 8) 6488 3369

The School of Mathematics and Statistics hosts the Mathematics & Statistics Colloquia.  This is a series of talks featuring high quality speakers drawn from our staff at UWA, further afield in Australia and also our international visitors. Each talk in the series is designed for a generalist audience with some mathematical background, and highlights an exciting aspect of Mathematics and Statistics. The School of Mathematics and Statistics warmly invites the wider university community to attend these talks. 

Talks are held on Thursdays at 4pm in the Blakers Lecture Theatre.  Following each colloquium cheese and wine is served upstairs in the Monadelphous building. Everyone is welcome to come along for this informal gathering and to have the opportunity to chat with the speaker.  

Following the reception we usually take the speaker to dinner.  Everyone is welcome to attend and continue your conversations.  For the purpose of restaurant reservations please advise Luke Morgan prior to the talk that you will be attending.     


 

Schedule


2017 Series

SpeakerDateAffiliationTitle
Dr. Tanya Schmah
26 October 2017
University of Ottawa
Geodesic motion in satellite attitude control and medical image analysis
Professor Steven Armfield
28 September 2017
The University of Sydney
Stability and transition for natural convection flow in inclined differentially side-heated cavities
Professor Tom de Medts
21 September 2017
Ghent University
Moufang sets: From permutation groups to non-associative algebras
Professor Dimitris Kugiumtzis
6 April 2017
Aristotle University of Thessaloniki
A linear Granger causality measure for high-dimensional time series
Professor Rebecca Waldecker
16 March 2017
Martin Luther University Halle-Wittenberg
Snowflakes, viruses and algorithms
Associate Professor Maria Vlasiou
15 February 2017
Eindhoven University Of Technology
AMSI-ANZIAM Public Lecture
Queues on Interacting Networks


2016 Series

SpeakerDateAffiliationTitle
Prof. Mikhail A. Vasiliev
24 November 2016
Lebedev Physical Institute of the Russian Academy of Sciences, Moscow
Joint Physics and Mathematics Colloquium:
Higher-Spin Gauge Symmetries and Space-Time
Prof. Peter Bouwknegt
15 November 2016
Mathematical Sciences Institute, ANU
Joint Physics and Mathematics Colloquium:
Dualities in Mathematics and Physics
Prof. Rod Gover
1 November 2016
The University of Auckland
Joint Physics and Mathematics Colloquium:
Conformal geometry and taming infinity
Prof. Snezhana Abarzhi
27 October 2016
The University of Western Australia
Rayleigh-Taylor instability and interfacial mixing
Prof. R. A. Bailey
6 October 2016
University of St Andrews
Design of dose-escalation trials: Research spurred by a trial that went wrong
Prof. Peter Cameron
15 September 2016
University of St Andrews
The random graph and its friends
A/Prof. Don Taylor
18 August 2016
University of Sydney
The Discovery of Janko's Sporadic Simple Groups
Dr Peter Neumann
2 June 2016
University of Oxford
Galois and his groups
Dr Nazim Khan
26 May 2016
The University of Western Australia
Who needs Mathematics and Statistics?
Prof. Adrian Baddeley
7 April 2016
Curtin University 
Mathematics and Statistics in Scuba Diving
Prof. Joy Morris
25 February 2016
University of Lethbridge 
Checkerboard tours


2015 Series

SpeakerDateAffiliationTitle
Prof. Andrew Bassom
19 November 2015The University of Western Australia
Grrrrr...linear stability should be simple - the saga of the Stokes' layer
Prof. Paul Baird22 October 2015Universite de Bretagne OccidentaleEncoding geometric information into combinatorial structure
Dr Francis Woodhouse13 August 2015The University of Western AustraliaMimicking magnets with lattices of bacterial vortices
Prof. Michael Shelley30 July 2015, 6pmNew York UniversityPublic lecture: Active and flexible bodies moving with(in) fluids
Dr Murray Elder21 May 2015Newcastle UniversitySolving equations in free groups
Dr Norman Do30 April 2015Monash UniversityCounting graphs, factorising permutations, and distinguishing knots
Prof. Michael Small19 March 2015The University of Western AustraliaComplex Systems: From nonlinear dynamics to graphs, via time series
Prof. Nozer D. Singpurwalla 19 February 2015City University of Hong KongThe Bayesian Paradigm for Statistical Inference and Decision Making
Dr Colva M. Roney-Dougal29 January 2015University of St AndrewsGroups, diagrams and geometries

Speakers and abstracts


2017 Series

 
Geodesic motion in satellite attitude control and medical image analysis: Dr. Tanya Schmah
Tanya Schmah

Abstract:
  Geodesics in Riemannian manifolds are paths that always go “straight ahead”. For example, the geodesics on a sphere are great circles. In classical mechanics, geodesic motion generalises Newton’s First Law and describes the motion of particles and rigid bodies in the absence of external forces. We discuss the example of rigid body motion and a novel method for controlling the attitude of satellites by adjusting their mass distribution. We also discuss geodesics in infinite-dimensional groups of diffeomorphisms and their role in medical image registration and shape analysis.

About the speaker:  Tanya Schmah is an Assistant Professor at the University of Ottawa, in the Department of Mathematics and Statistics.  A graduate of UWA in Maths and Computer Science, she has worked in both industry and academia. She earned her PhD in 2001 from the EPFL (Switzerland) with a thesis in geometric mechanics, a subject on which she later co-authored a graduate text.
She was a Lecturer in Maths at first the University of Warwick and then Macquarie University. In 2007 she moved to the University of Toronto and into the fields of statistical machine learning and neuroinformatics. Her main current research interest is the application of geometry and machine learning to neuroimage registration and analysis, with a particular focus on stroke lesion mapping. 

 
Stability and transition for natural convection flow in inclined differentially side-heated cavities: Prof. Steven Armfield
Steven Armfield

Abstract:
  Natural convection flow in a differentially heated square cavity,where opposing vertical walls are heated and cooled, has been widelystudied, providing a canonical representation of a large range ofbuoyancy driven flows. The flow consists of natural convectionboundary layers forming on the heated/cooled walls, entraining fluidfrom, and discharging to, the stratified interior.  The overall flowacts to transport heat from the heated to the cooled wall, with thedetails of the flow depending on the temperature difference betweenthe sidewalls, typically characterised by a Rayleigh (or Grashof)number, and on the Prandtl number of the fluid.  As the cavity isinclined so that the heated wall is below the cooled wall, thestructure of the flow changes such that the boundary layers formed onthe heated and cooled sides retain their structure adjacent to theadiabatic sides. This allows travelling waves to circulatecontinuously around the cavity, providing a feedback mechanism toaugment the convective instability of the natural convection boundarylayers, leading to an absolute instability of the total flow, withassociated bifurcation, at a specific inclination angle.  Results willbe presented detailing this change in flow structure and associatedbifurcation and transition, as well as its influence on the bulk heattransfer.

About the speaker:  Professor Steve Armfield investigates the fluid mechanics of a range of environmental and industrial flows using computational, theoretical and experimental approaches, leading to applications as diverse as improved river management and the design of more efficient building ventilation systems. His research has made a substantial contribution to the understanding of the mechanism of flow initiation and transition. 
Professor Armfield joined the academic staff of the University of Sydney in 1996, having previously completed a PhD there. He was Head of the School of Aerospace, Mechanical and Mechatronic Engineering from 2008 till 2015. He has held academic positions at other Australian universities as well as research positions in Japan and the US. 

 
Moufang sets: From permutation groups to non-associative algebras: Prof. Tom de Medts
Tom de Medts

Abstract:
  A Moufang set is a notion from permutation group theory with a very basic definition, aiming to axiomatize the fact that the group has "rank one" in a suitable sense. A typical example is the group PSL_2(R) acting on the real projective line. Important examples of Moufang sets arise from linear algebraic groups of relative rank one (over arbitrary fields).
Interestingly, there are deep connections between Moufang sets and certain classes of non-associative algebras, such as Jordan algebras and the not so well known structurable algebras. These are, in turn, related to Lie algebras and to linear algebraic groups (again).The aim of the talk is to give an overview of this theory for a general mathematical audience. We will include examples and point out how the different aspects come into play.

About the speaker:  Tom obtained his PhD in January 2003 under the joint supervision of Hendrik Van Maldeghem (Ghent University, Belgium) and Richard Weiss (Tufts University, Boston, USA). He continued to do a postdoc funded by the FWO (Science Foundation, Flanders, Belgium) at Ghent University, where he was appointed professor in 2007.
The main theme of his current research is connecting non-associative algebras to other areas of mathematics, such as group theory and building theory, but also includes other aspects, such as Lie theory, topological groups, model theory and incidence geometry.
He loves to be involved in large and challenging projects, and he has been the supervisor of 6 finished and 3 ongoing PhDs. 

 
A linear Granger causality measure for high-dimensional time series: Prof. Dimitris Kugiumtzis
Dimitris Kugiumtzis

Abstract:
  Granger causality is a statistical concept stemming from econometrics and regards the effect of one variable on the time evolution of another variable. Measures of Granger causality have been employed for the investigation of the inter-dependence structure of complex systems and the formation of complex networks. Though most complex systems are inherently nonlinear and thus only nonlinear Granger Causality measures are in principle appropriate, often the limitations of noise and time series length suggest the use of linear Granger causality measures. In the presence of many observed variables, even linear Granger causality measures may collapse due to the instability of the estimation of vector autoregressive models (VAR) of many variables on time series of limited length (large number of coefficients of lagged variables to be estimated). For this, restrictions on the lagged variables have been suggested under the term variable selection, dimension reduction or sparsity of the VAR model, and the most popular method for this purpose is LASSO. In this study, a different approach is followed, and the VAR model is built up by means of a progressive search for lagged variables, applying a modification of the so-called backward-in-time selection method. The new method is compared favorably to LASSO and other VAR restriction schemes, using linear stochastic multivariate systems of different number of variables and lengths of the generated time series. It is also demonstrated on a real-world example of human scalp multi-channels electroencephalograms measured during epileptiform discharges.

About the speaker:  Dimitris Kugiumtzis (BSc in Mathematics at the Aristotle University of Thessaloniki (AUTh), Greece, MSc and PhD in Informatics at the University of Oslo, Norway) is Professor at the Department of Electrical and Computer Engineering, AUTh, Greece. He has been member of staff in AUTh since 2001. He was Lecturer B at the Department of Statistics, University of Glasgow, UK (2000-2001) and guest scientist (Postdoc) at the Max Planck Institute for Physics of Complex Systems, Dresden, Germany (1998-1999). His main research area is time series analysis in conjunction with dynamical systems, chaos and complexity, as well as computational statistics and data mining. Applications extend from neuroscience to climate and finance. He has published over 60 journal papers and many international and national proceedings papers. He has participated in several national and European research projects, acted as EU evaluator and regular reviewer for a number of journals. He currently supervises 2 PhDs and 6 MScs, and has supervised 5 completed PhDs and over 30 MScs. 

 
Snowflakes, viruses and algorithms: Prof. Rebecca Waldecker
Rebecca Waldecker

Abstract:
  In this talk we will look at different objects that have one thing in common: they exhibit symmetry. Why is this relevant? How can we grasp the concept of symmetry mathematically and how can we understand it? Inspired by examples, we will look at symmetry and discuss how it can be used to simplify complex calculations, to understand and classify objects from real life, and to improve algorithms.

About the speaker:  Professor Rebecca Waldecker is the 2017 Cheryl Praeger Visiting Research Fellow. Rebecca finished her university degree in mathematics, econometrics and statistics at the University of Kiel (Germany) in 2003 and stayed there for her PhD, supervised by Helmut Bender. In 2007 she went to the University of Birmingham - first as an Honorary lecturer, and then as a Research Fellow on a project with Paul Flavell, funded by the Leverhulme Trust.
She returned to Germany in 2009 as a junior professor. Since then, she has been working at the University of Halle and has been appointed a full professor in 2015. Her research is mostly in finite group theory and covers abstract results as well as applications, e.g. in computer algebra. She teaches university courses on all levels as well as summer academy courses, and she enjoys the wide range of research projects with her colleagues and her students. 

 
AMSI-ANZIAM Public Lecture - Queues on Interacting Networks: A. Prof. Maria Vlasiou
Maria Vlasiou

Abstract:
  We have all had the unpleasant experience of waiting for too long at some queue. We seem to lose a significant amount of time waiting for some operator to reply to our call or for the doctor to be able to see us. Queues are the object of study of queuing theory, i.e., the branch of applied mathematics that studies models involving a number of servers providing service to at least one queue of customers. Queues are an example of a stochastic process and a group of connected queues is an example of a network.
In this talk, we will give a brief overview of the area of stochastic processes, ranging from classroom examples to their impact on industry and technology. We then introduce networks with interacting architectures and look at different architectures through examples. The aim is to give an idea of the mathematical challenges that these interactions create and the importance of incorporating this level of detail in mathematical analysis. 

About the speaker:  Maria Vlasiou is an Associate Professor in the Department of Mathematics and Computer Science at the Eindhoven University of Technology (TU/e), a Research Fellow of the European research institute Eurandom, and Scientific Staff member of CWI. Born in Greece in 1980, she received her B.Sc. (2002, Hons.) and Ph.D. (2006) from the Aristotle University of Thessaloniki and TU/e, respectively. Her research interests centre on stochastic processes and stochastic operations research. Her research focuses on the performance of stochastic processing networks with layered architectures and on perturbation analysis for heavy-tailed risk models. Other interests include Lévy processes, large deviations for non-monotone stochastic recursions, and proportional fairness in heavy traffic for bandwidth-sharing networks.
Dr. Vlasiou’s research so far has been funded by grants from more than 10 science foundations, universities, societies, and organisations. She is the co-author of more than 30 refereed papers, the co-recipient of the best paper award in ICORES 2013, the Marcel Neuts student paper award in MAM8, and of the 3rd prize of the 8th conference in Actuarial Science.   

  
            

2016 Series

 
Higher-Spin Gauge Symmetries and Space-Time: Professor Mikhail A. Vasiliev
Mikhail A. Vasiliev

Abstract:
  Higher-spin gauge theory is a theory exhibiting an infinite extension of usual space-time and internal symmetries of modern models of fundamental interactions. I will discuss general aspects of the higher-spin gauge theory with the emphasis on the higher-spin symmetry and its implications for fundamental concepts of space-time.

About the speaker:  Professor Mikhail Vasiliev is one of the creators of higher-spin gauge theory, which belongs to the most active research areas of modern theoretical high-energy physics. He received his PhD in 1980 and his habilitation degree in 1992, both from the Lebedev Physical Institute of the Russian Academy of Sciences, one of the largest Russian research centres (and home to seven Nobel Laureates). From 2000 till 2012 Professor Vasiliev was Head of the Theory Division of the Lebedev Physical Institute. At present, he is a Principal Researcher and Leader of the Quantum Field Theory Group at the Lebedev Physical Institute.In 2014 Professor Vasiliev held the prestigious honorary Kramers Chair for Theoretical Physics at the University Utrecht. Since the establishment of the Kramers Chair in 1975, there have been 31 occupants, the first of whom was the Nobel Laureate Eugene Wigner.In 2016 Professor Vasiliev was awarded the I. E. Tamm Gold Medal of the Russian Academy of Sciences.Mikhail Vasiliev is famous for the nonlinear equations describing the dynamics of massless higher- spin fields, also known as the Vasiliev equations. 

    
Dualities in Mathematics and Physics: Professor Peter Bouwknegt
Peter Bouwknegt

Abstract:
  In this talk I will review some geometric analogues of the Fourier transform, which arise in String Theory under the name of ‘dualities’.  In particular, I will discuss global aspects of T-duality and mention some recent generalisations.  T-duality hasimportant applications in different areas of mathematics, such as indifferential geometry, algebraic topology, operator algebras,noncommutative geometry, as well as in physics.  This is a talk aimed at non-specialists and will include many examples.

About the speaker:  Professor Peter Bouwknegt studied Theoretical Physics and Mathematics at the University of Utrecht, Netherlands, under supervision of Prof G 't Hooft (Nobel Prize for Physics 1999), and at the University of Amsterdam under Prof FA Bais.  He obtained his PhD in 1988.  He then spent several years as a postdoctoral fellow at MIT, CERN and the University of Southern California before settling in Australia in 1995. He spent almost 10 years at the University of Adelaide, first as an ARC QEII Fellow and subsequently as an ARC Senior Research Fellow, before being appointed Professor of Theoretical Physics and Mathematics at the Australian National University in 2005. He is a recipient of the 2001 medal of the Australian MathematicalSociety, and an expert on the mathematical foundations of String Theory and Conformal Field Theory. He served on the Australian Research Council's College of Experts from 2009-2011, and 2014-2016, and the ERA-REC in 2012. He is currently the Director of the Mathematical Sciences Institute at the ANU. 

 
Conformal geometry and taming infinity: Professor Rod Gover
Rod Gover

Abstract:
  The world around us appears to involve lengths and angles. From these  emerge the classical notions of shape and symmetry configured in 3  dimensions. Our mathematical ancestors realised that these notions  should be important, not only for construction and surveying, but also  for understanding "life, the universe and everything". In the process of  simplifying complicated structures it turns out that an important role  is played by conformal geometries - these are spaces where there is a  notion of angle but not length.
We will discuss some elegant tools for working with these less than rigid geometries and how they help treat other problems such as writing massive particle equations and taming non-compact spaces. 

About the speaker:  Rod Gover is a Professor of Mathematics at the University of Auckland and a Fellow of the Royal Society, New Zealand. His research develops mathematical theory for application to problems in differential geometry, analysis, complex analysis, and mathematical physics. A current focus is the treatment and use of a class of structures known as Cartan geometries.  This area has close connections to Lie theory, including the representation theory of semisimple Lie groups, as well as the analysis of differential equations.
He currently leads a project funded by the Royal Society of New Zealand Marsden Fund titled "New directions at the geometry-analysis frontier". 

  
Rayleigh-Taylor instability and interfacial mixing: Professor Snezhana Abarzhi
Snezhana Abarzhi

Abstract:
  Rayleigh-Taylor instability (RTI) develops when fluids of different densities are accelerated against their density gradient. Extensive interfacial mixing of the fluids ensues with time. Rayleigh-Taylor (RT) mixing controls a broad variety of processes in fluids, plasmas and materials, in high and low energy density regimes, at astrophysical and atomistic scales. Examples include supernova explosion, flows in atmospheres and oceans, oil recovery and fluid atomisation. In some of these cases (e.g. inertial confinement fusion) RT mixing should be mitigated; in others (e.g. turbulent combustion) it should be enhanced. Understanding the fundamentals of RTI is crucial for achieving a better control of non-equilibrium processes in nature and technology.
Traditionally, it was presumed that RTI leads to uncontrolled growth of small-scale imperfections, single-scale nonlinear dynamics, and extensive mixing that is similar to canonical turbulence. Recent theoretical and experimental developments suggest an alternative scenario of RTI evolution: the interface is necessary for RT mixing to accelerate, the acceleration effects are strong enough to suppress turbulence at large scale, and the RT dynamics is multi-scale and well correlated. This talk presents a rigorous symmetry-based consideration of the fundamentals of RTI and RT mixing, and summarises what is certain and what is not so certain in our knowledge of RTI. We focus on the question - Is RT interfacial mixing a disordered process indeed? We also discuss new opportunities for improvements of predictive modelling capabilities, physical description, and control of RT mixing in fluids, plasmas and materials.

About the speaker:  Snezhana Abarzhi works at The University of Western Australia as Professor of Applied Mathematics. After getting her PhD degree (Moscow Institute for Physics and Technology and Landau Institute for Theoretical Physics), Dr. Abarzhi worked at internationally recognised research institutions [Carnegie Mellon University, University of Chicago; Stanford University; Osaka University; State University of New York at Stony Brook; University of Bayreuth; Landau Institute and High Energy Density Institute of the Academy of Sciences, Russia].
Her research contributions have been recognised with international awards (US National Science Foundation, Japan Society for the Promotion of Science, Russian Academy of Sciences, and Alexander von Humbolt Foundation).
The focus of Dr. Abarzhi’s research is on Rayleigh-Taylor instabilities and turbulent mixing. Her contribution to this field is development of rigorous and physics-based theoretical approaches that identify the fundamentals of Rayleigh-Taylor instabilities and mixing. The main results are: order in Rayleigh-Taylor mixing; multi-scale dynamics of nonlinear Rayleigh-Taylor instabilities; group theory approach for analysis of unstable interfacial dynamics. 

 
Design of dose-escalation trials: Research spurred by a trial that went wrong: Prof. R. A. Bailey
Rosemary Bailey

Abstract:
  In March 2006 the topic of designed experiments briefly hit the British newspaper headlines when a clinical trial near London went badly wrong.  When a working party of the Royal Statistical Society looked into this, my experience from designing experiments in other areas, such as agricultural field trials and microarray experiments, proved useful in improving the design of dose-escalation trials to obtain better information without compromising safety or using more volunteers.  I shall say something about the recommendations of the RSS working party, something about the ethical constrains on Phase I clinical trials, and something about the new designs.

About the speaker:  R.A. Bailey's statistical life began as a technician in Air Pollution Research, processing data in the pre-computer age.  Then she did a Mathematical degree at the University of Oxford, following this with a year on Voluntary Service Overseas teaching Mathematics and French in a school in Nigeria, before returning to Oxford to do a doctorate in finite group theory.  After a few years at the fledgling Open University, she learnt how to apply group theory to the design of experiments while a post-doctoral researcher at the University of Edinburgh.  She spent ten years as a statistician in agricultural research at Rothamsted Experimental Station, before returning to academic in the University of London, first at Goldsmiths College, then at Queen Mary University of London.  Since retiring from QMUL in 2012, she is enjoying a half-time position at the University of St Andrews.
 
The random graph and its friends: Prof Peter Cameron
 

Peter Cameron


Abstract:
 
 There is a countably infinite graph R (first explicitly constructed by Richard Rado) with the following remarkable property:  if we choose a countable random graph by selecting edges independently with probability 1/2, then with probability 1 it is isomorphic to R.  (This fact was implicit in a paper of Erdos and Renyi at about the same time as Rado's construction.)  The graph has many other surprising properties, and occurs in a number of guises.

It turns out that the graph is produced by a construction by Fraisse more than ten years earlier, which builds homogeneous relational structures (in which any isomorphism between finite structures extends to an automorphism) with prescribed finite substructures, and shows its uniqueness.  But even Fraisse had been anticipated by Urysohn, who showed (in a posthumous paper a quarter of a century earlier) that there is a unique homogeneous Polish space (complete separable metric space) containing all finite metric spaces.

It is natural to ask what happens if we dualise Fraisse's construction by turning the arrows around.  There is indeed a dual construction; among other things it gives a new way to build a remarkable topological space, the pseudo-arc. 


About the speaker:  Peter Cameron was born in Toowoomba, and studied at the University of Queensland before taking his DPhil at Oxford University under Peter Neumann's supervision. [Note: all this is also true of Cheryl Praeger!]  Subsequently he held positions at Oxford, at Queen Mary University of London, and currently at the University of St Andrews.  He won the London Mathematical Society's Junior Whitehead Prize in 1979, and the Institute of Combinatorics and its Application's Euler Medal in 2003.  His work is mainly in permutation groups, but this spills over into algebra, combinatorics, logic, and topology.  His Erdos number is 1; the Cameron-Erdos conjecture was subsequently proved by Ben Green.

 
 

The Discovery of Janko's Sporadic Simple Groups: A/Prof Don Taylor

Don Taylor

 
 

Abstract:  In 1966, Zvonimir Janko published a paper which revolutionised finite group theory.  The previous year, working as a Research Fellow at the Institute of Advanced Study within the Australian National University, Janko constructed a new simple group which was neither an alternating group nor a group of Lie type.  The 1966 paper contains the complete details.
Before 1965 only five sporadic simple groups were known.  They had been discovered almost exactly one hundred years prior (1861 and 1873) by Emile Mathieu but it was not until 1900 that G.A. Miller proved their simplicity.By 1976 the number of new sporadic simple groups had risen to 21 and Janko had found four of them, including the first and the last.  This talk recounts some of the history of those exciting times.

 

About the speaker:    In 1968 Don Taylor graduated from Monash University with an MSc supervised by Professor Zvonimir Janko.  He then travelled to the University of Oxford where he completed a DPhil with Professor Graham Higman FRS.
In 1972 Don took up a lectureship at La Trobe University and in 1975 he moved to Sydney where he has been ever since. He has written several books on group theory, the most recent (with Gus Lehrer) on complex reflection groups.
Since 2007 Don has been an Honorary Associate Professor at the University of Sydney, working on reflection groups and algorithms for groups of Lie type. 

   
 

 Galois and his groups:  Dr Peter Neumann

 
 

Dr Peter Neumann

 
 

Abstract:  When Galois invented groups they were very different from the structures taught and learned and loved in undergraduate courses at UWA and other modern universities.  My purpose in this lecture will be to explain the differences and calibrate the similarities.  As a by-product I hope to show that topics in the History of Mathematics can be just as exciting, subtle and difficult as mathematics itself. 


 

About the speaker: Peter was awarded a DPhil in 1966, written under the supervision of Professor Graham Higman FRS, and a DSc by Oxford in 1976.  In Oxford, Peter 38 students completed doctorates under his supervision, including one Cheryl E. Praeger.
Peter has been honoured with the Lester R. Ford Award by the Mathematical Association of America in 1987, the Senior Whitehead Prize by the London Mathematical Society in 2003, and the David Crighton Medal jointly by the Institute of Mathematics and its Applications and the London Mathematical Society in 2012.  Peter was elected to an Emeritus Fellowship of Queen's in 2008.
Peter's research has contributed to a range of areas of algebra and its history.  Some include:  finite permutation groups; infinite permutation groups; soluble groups; design of group-theoretic algorithms, history of group theory. 

     
 

Who needs Mathematics and Statistics?:  Dr Nazim Khan

 
 

Dr Nazim Khan

 

Abstract:   Most Australian universities have replaced mathematics pre-requisites with assumed knowledge for entrance requirements.  Exactly what knowledge is assumed and what steps are taken to remedy and lack of mathematics knowledge?  I will report on two pilot studies.  The first is of Science and Engineering students investigating their assessment of the mathematics requirements for their course, their mathematics background and mathematics preparation offered by their institution.  The importance of mathematics and statistics for their course will also be discussed.  The second is an investigation of PhD thesis in Science in Australian universities regarding the quality of statistical analysis.  PhD theses were selected as they are the stepping stone to research and innovation.
The results of both studies are relevant to Australia's future in the competitive global market. 
Note:  The first project was conducted as a third year student project, with Gavin Race, Udara Wickramage, Lewis Teixeira, Mark Ridgwell.


About the speaker:    Nazim Khan was born in Fiji and came to Australia as a student on an Australian Commonwealth scholarship.  He completed a B.E. (electrical) and worked in Fiji for three years.  He returned to Perth and took up a position as tutor in The School of Electrical and Electronic Engineering in 1986.  Nazim then completed a BSc. with honours (Maths and Stats) and then a PhD.  Nazim has worked as a research assistant with Professor Geoff MacLachlan and also as a statistical consultant at UQ (2002-2003).  He has also taught at Griffith University, UQ and QUT. His current appointment is at UWA (2004).  His research interests are in Markov models, linear models, computational statistics, missing data and applications.  He is also very interested in teaching and learning matters in Mathematics and Statistics, and is well known internationally in STEM education circles.

 
 

Mathematics and Statistics in Scuba Diving:  Professor Adrian Baddeley

 

 Dr Adrian Baddeley

Abstract:  Scuba divers are trained to follow procedures that keep them safe while diving and afterward.  Surprisingly, these safety measures are based on just a handful of simple mathematical and statistical principles, which will be explained in this colloquium.  Better public understanding of these basic principles would dispel many common misconceptions about scuba safety.  Modern diving practices also pose some challenging mathematical problems, with interesting solutions, which are often treated as an industrial secret by the manufacturers of safety devices. 


About the speaker: Adrian Baddeley PhD DSc FAA is Professor of Computational Statistics at Curtin University in Perth, Australia.  He is a former UWA Professor and Head of Department, and now Adjunct Professor.  Adrian is a keen diver with over 1100 scuba dives logged.  He has recently published 3 journal papers on scuba decompression theory and scuba accident statistics.  



 
 

Checkerboard tours:  Professor Joy Morris

 
 

Dr Joy Morris

 

Abstract:  Place a checker on one corner of a checkerboard. Can the checker tour the whole board? Where can such a tour end? What if we vary some of the rules:
 - choosing whether or not the tour has to end where it began; 
 - allowing the checker to step off the edges of the board; and 
 - restricting the directions in which the checker can travel?
These questions all fit into the general framework of Hamilton cycles and paths in Cayley graphs and digraphs, but I will focus on the questions as they apply to checkerboards. Even in this simple setting, the answers can get surprisingly complex, and there are things we don’t know.


About the speaker: Joy Morris was born in Canada. After completing a Bachelor’s degree in Math and English at Trent University, she went on to do her PhD in algebraic graph theory at Simon Fraser University in Vancouver under the supervision of Brian Alspach. She graduated in 2000, and has been working at the University of Lethbridge in Alberta, Canada since then. She received a University Faculty Award from Canada’s national research agency (NSERC) in 2001, a prestigious grant that supports promising young researchers by reducing their teaching requirements for 5 years. She was promoted to full Professor in 2015.
 Joy has 36 publications that have appeared or been accepted, in journals including the Transactions of the American Math Society. She has been an invited speaker at a number of international conferences in Slovenia, China, and Canada.

            

2015 Series

 
 
Grrrrr...linear stability should be simple - the saga of the Stokes' layer  : Prof Andrew Bassom
 
 

Andrew Bassom

 

Abstract:
 
 The linear stability of boundary layers is a subject which was thought to have been essentially solved long ago. During my interview at UWA over 12 years ago I talked about some calculations directed towards understanding the stability properties of a Stokes layer, which is the fluid flow set up when an oscillatory viscous flow moves over a rigid boundary. Those computations gave results very different from experimental observations and it is only relatively recently that we believe we have found a plausible explanation for the discrepancy. Here I shall review a number of the various frustrations experienced in the research into this ostensibly straightforward problem (and conclude that I should have given up long ago).  


About the speaker:  After a PhD and postdoc at Exeter (UK), Andrew stayed on there as first a lecturer, then a reader, in applied mathematics. He has worked in a wide variety of topics including mathematical modelling and differential equations. However the majority of his research encompasses various aspects of stability of fluid flows. Andrew took up a chair at UWA at the beginning of 2005 and served as Head of School of Mathematics & Statistics for the years 2009-14. This colloquium marks Andrew's last lecture at UWA, as he leaves in a few days to take up a fresh challenge at the University of Tasmania in Hobart.

  
Encoding geometric information into combinatorial structure  : Prof Paul Baird
 
 

Paul Baird

 

Abstract:
 
 There may be several reasons why we might wish to encode geometric information in this way:  to transmit 3D-images; to provide algorithms by which an autonomous robot may navigate in the world; to optimise complex networks.  My approach will be to consider how we ourselves reconstruct 3D-images, or frameworks, from suitably drawn lines on a piece of paper, the so-called Gestalt effect.  One crucial aspect that I wish to capture is invariance with respect to similarity transformations, so that the geometry of the framework doesn't depend upon the way in which it is embedded in space, or in other words, the perspective from which it is viewed.  To do this I will consider a set of equations that one can associate to a combinatorial graph which define its "geometric spectrum".  An element of the spectrum allows one at least locally to realise the graph as an invariant framework in Euclidean space. Comparison with smooth counterparts provides insight into the interpretation of the equations.  Very little background is required to follow this talk:  a basic knowledge of complex numbers, linear algebra and the geometry of curves and surfaces would be useful.  


About the speaker:  Paul Baird is Professeur Classe Exceptionnelle at the Université de Bretagne Occidentale in Western Brittany, France.  He heads the Topology and Geometry group of its Research Institute of Mathematics and is a coordinator of a Franco-Spanish project on Geometric Analysis.  Paul has received numerous grants, among them a Marie Curie intra European Fellowship for career development.  He is well known for his ground-breaking work on harmonic mappings and his contributions to the study of the Ricci flow; notably in the construction of the first known examples of non-gradient solitons, fundamental to the understanding of the long term behaviour of solutions.  Paul has also co-authored a London Mathematical Society Monograph and is the editor of four books.

  
Mimicking magnets with lattices of bacterial vortices: Dr Francis Woodhouse
 
 

Dr Francis Woodhouse

 

Abstract:
 When alone in an unbounded fluid, a rod-shaped motile bacterium like E. coli will swim in straight lines punctuated by random turns.  Pack many of them together in the same fluid, however, and they adopt collective swirling patterns akin to macroscopic turbulence.  Confining the bacteria within a small circular cavity tames this turbulence and leads instead to a steadily spinning bacterial vortex.  When many such vortices are linked together in a square lattice of cavities, the rotation sense of a vortex becomes dependent on those of its neighbours.  By declaring the senses to be 'up' and 'down' spins, the result is a bacterial analogue of an Ising ferromagnet.  After explaining the background to these so-called 'active matter' systems, I will explore the challenges involved in mapping classical statistical physics models to this decidedly non-classical system - but only after revealing an entirely unexpected twist in the experiments. 


About the speaker:  Dr Francis Woodhouse is a postdoctoral researcher at The University of Western Australia. Before moving to Perth, he studied mathematics at the University of Cambridge, first as an undergraduate and then for his PhD in microbiological continuum mechanics. He balances himself on the interface between mathematics and biology and is currently interested in problems of cartilage biomechanics, renal dysfunction and the collective dynamics of bacteria.

  
Public lecture - Active and flexible bodies moving with(in) fluids : Professor Michael Shelley
 
 

Michael Shelley

 

 

Abstract:  We are surrounded by structures that move and interact with a fluid - a flag flaps in a stiff breeze, a bird flies overhead, or a microscopic bacterium swims across a droplet of water.  The study of how such immersed bodies interact with fluids has a long and interesting history, and defines a class of "moving boundary problems" that are central to science.  What makes such problems especially difficult, and so fascinating for an applied mathematician, is that the dynamics of body and fluid are intimately intertwined and must be treated in an integrated way.  I will discuss fluid-structure interactions ranging those we can directly see, like flapping flags and flying birds - to those we cannot - such as collective behaviours of swimming microbes and the transport of structures in biological cells.  These examples will make clear the absolutely fundamental role that size plays in organizing our understanding. 

 
 


About the speaker: Michael J. Shelley is an American applied mathematician who works on the modelling and simulation of complex systems arising in physics and biology. This has included free-boundary problems in fluids and materials science, singularity formation in partial differential equations, modeling visual perception in the primary visual cortex, dynamics of complex and active fluids, cellular biophysics, and fluid-structure interaction problems such as the flapping of flags, stream-lining in nature, and flapping flight.

  
Solving equations in free groups : Dr Murray Elder
 
Dr Murray Elder
 
 


Abstract:
  An equation in a free group is an expression U=V where U,V are words over elements of the group and variables X,Y,Z, etc.  A solution is an assignment of group elements to the variables which make the equation true.
In the 1970s, Makanin constructed a (really complicated) algorithm which decides if an equation has a solution or not.  Later, Razborov extended Makanin's result to find all solutions.  The complexity of these algorithms was subsequently shown to be pretty bad.
In this talk I will present a new approach, describing a finite graph that encodes all solutions in reduced words, which has exponential size and can be constructed in nondeterministic quasilinear space (in the length of the equation). I will try to motivate and explain the problem, how it relates to some questions in logic, and give some of the ingredients of the proof.
This is joint work with Laura Ciobanu, Neuchatel and Volker Diekert, Stuttgart.

 

 About the speaker:  Murray did an undergraduate applied science degree at LaTrobe-Bendigo 1991-1993, then a postgrad diploma and coursework masters at Melbourne Uni, getting an APA to do a PhD at Melbourne under Walter Neumann, working on geometric and automatic group theory.  He then got postdocs at Texas A&M, Tufts (Boston), St Andrews (Scotland) and lecturing positions at Wollongong, Stevens (USA) and Queensland before coming to Newcastle in 2011.  In 2011 he scored a Future Fellowship from the ARC to work on algorithmic and computational problems in infinite group theory.

  
Counting graphs, factorising permutations and distinguishing knots : Dr Norman Do
 
Dr Norman Do
 

 
Abstract: How many trees (graphs without cycles) with a given number of edges can be drawn in the plane? A natural generalisation is to count graphs embedded in more complicated surfaces. This enumeration is governed by two simple objects - a "spectral curve"and a "quantum curve" - that are related by a mysterious process called "quantisation".  We will discuss exactly what this means and why it is mysterious, before observing the same structure in problems that involve permutation factorisations and knot invariants.
 

About the speaker:  Norman Do is, first and foremost, a self-confessed maths geek!  As a high school student, he represented Australia at the International Mathematical Olympiad.  He completed a PhD at The University of Melbourne, before working at McGill University in Canada.  He is currently a Lecturer and a DECRA Research Fellow in the School of Mathematical Sciences at Monash University. His research lies at the interface of geometry and mathematical physics, although he is excited by almost any flavour of mathematics. Norman is heavily involved in enrichment for school students, regularly lecturing at the National Mathematics Summer School and currently chairing the Australian Mathematical Olympiad Senior Problems Committee.
  
Complex Systems: From nonlinear dynamics to graphs, via time series : Prof Michael Small
 
Prof Michael Small
 
 


Abstract:
  Given a deterministic dynamical system - possibly contaminated by noise - what can I say about that system by measuring the time evolution of a single state? There are standard methods to answer this question, and I will review these. I will also show that by transforming the reconstructed system into a large graph, it is possible to learn even more.

 

About the speaker:  Michael started his academic career with an honours degree (second class) in Pure Mathematics, quickly followed by a PhD in Applied Mathematics - both from UWA. Following a brief stint consulting for an investment bank in South Africa, and a post-doc in Physics in Scotland, he took up a faculty position in Electronic Engineering at the Hong Kong Polytechnic University. Michael's research interests are in nonlinear dynamics, nonlinear time series analysis, complex systems and complex networks.  He returned to UWA in 2012.

  
The Bayesian paradigm for statistical inference and decision making : Prof Nozer D. Singpurwalla
 
Prof Nozer Singpurwalla
 
 


Abstract:
  In this expository talk, open to a general audience, I outline the essence of the Bayesian paradigm for inference and decision making. After an overview of the subjective nature of probability, I discuss the notion of a likelihood, and the genesis of a probability model. The material here is standard, but the perspective is not. It will be illustrated by some simple examples.

 

About the speaker:  Professor Singpurwalla is a Chair Professor at the City University of Hong Kong. He is also an Emeritus Professor of Statistics and Distinguished Research Professor at the George Washington University in Washington, D.C. He has been Visiting Professor at Carnegie-Mellon University, Stanford University and Oxford University (UK). He is Fellow of the Institute of Mathematical Statistics, the American Statistical Association, and the American Association for the Advancement of Science, and he is an elected member of the International Statistical Institute. He is the 1984 recipient of the U.S. Army's S. S. Wilks Award for Contributions to Statistical Methodologies in Army Research, Development and Testing, and the first recipient of The George Washington University's Oscar and Shoshana Trachtenberg Prize for Faculty Scholarship.

  
Groups, diagrams and geometries : Dr Colva M. Roney-Dougal
 
Dr Colva Roney-Dougal
 

Abstract:
  The study of finitely-presented groups has been ongoing since the work of Hamilton in the 1850s - almost as long as group theory itself! This talk will be a gentle introduction to finitely-presented groups, with an emphasis on algorithms. I will describe some finite diagrams and some potentially infinite geometries, that are naturally associated with any finitely-presented group and show how results about the diagrams and geometries prove structural results about the group and vice versa.

About the speaker:  Colva Roney-Dougal is a Reader in Pure Mathematics at the University of St Andrews, where she is the Director of the Centre for Interdisciplinary Research in Computational Algebra. After completing an undergraduate degree at St Andrews, she did her PhD at Queen Mary, University of London. She is the 2015 Cheryl E. Praeger Visiting Research Fellow. Colva Roney-Dougal's research centres on group theory, she has done considerable work on the development of fast algorithms for finite and infinite groups. As well as her academic work, she has done a great deal of mathematics popularisation, including several radio shows with Melvyn Bragg and one with Brian Cox.

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