What's On at UWA

Groups and Combinatorics Seminar

Irene Pivotto (UWA)

will speak on

Packing Steiner trees

at 1pm Tuesday 2nd of October in MLR2

Abstract: A classic theorem of Nash-Wiliams and Tutte gives necessary and sufficient conditions for a graph to have k pairwise edge-disjoint spanning trees. We will discuss the natural generalization of this problem to trees spanning a distinguished set of vertices (which we refer to as Steiner trees). Finding edge-disjoint spanning trees is a considerably easier problem that finding edge-disjoint Steiner trees. This is due to the fact that spanning trees are bases of the natural matroid associated with a graph, while Steiner trees are not bases of any matroid. We will present a result that provides sufficient conditions for the existence of k edge-disjoint Steiner trees, reducing this problem to finding disjoint bases of a particular matroid. No prior knowledge of matroid theory is required to attend the talk.

As part of a tradition at the University Physics Screening, fortnightly screenings of various Science Fiction Movies, documentaries and famous recorded lectures will continue screening weekly all through this semester.

This week's screening features the famous cult-hit movie classic Donnie Darko by Richad Kelly.

FREE ENTRY, and drinks and snacks can be purchased at the door

Groups and Combinatorics Seminar

Michael Giudici (UWA)

will speak on

Commuting graphs of groups

at 1pm Tuesday 9th of October in MLR2

Abstract: The commuting graph of a group G is the graph whose vertices are the noncentral elements of G and two vertices are adjacent if and only if they commute. Iranmanesh and Jafarzadeh conjectured that the commuting graph of a finite group is either disconnected or has diameter bounded above by some constant. I will discuss recent joint work with Chris Parker on this conjecture.

You might have a great idea, but are you ready for the business world?

Whether you are working on a specific project or have a bunch of ideas that might be a future business or product, this workshop will help you get started!

Our presenter, Jane Garrett is an entrepreneur with firsthand experience of the path to success and can help you develop your skills. Jane is passionate about innovation and entrepreneurship and is the instigator and program director of the inspirational ‘Ignition’ program for inventors and business developers at the Curtin Centre for Entrepreneurship. Jane is also a regular contributor to the WA Innovator of the Year program and part of the WA Innovation Centre Team.

Come and join the discussions and learn!

Register your interest with Kerry for a tour of the Scitech workshop where we make our amazing exhibitions. Tour will start at 3.00pm. Refreshments and complimentary entry to Scitech are included in the ticket price.

A Public Lecture by Professor J. Hyam Rubinstein, Department of Mathematics & Statistics, University of Melbourne.

The Poincare conjecture was one of the most celebrated questions in mathematics. It was amongst the seven millennium problems of the Clay Institute, for which a prize of $1million was offered.

The Poincare conjecture asked whether a 3-dimensional space with `no holes’ is equivalent to the 3-dimensional sphere.

In 2003 Grigori Perelman posted three papers on the internet ArXiv outlining a marvellous solution to the Poincare conjecture, as part of the completion of Thurston’s geometrisation program for all 3-dimensional spaces. Perelman introduced powerful new techniques into Richard Hamilton’s Ricci flow, which `improves’ the shape of a space. Starting with any shape of a space with no holes, Perelman was able to flow the space until it became round and therefore verified it was a sphere.

A brief history of the Poincare conjecture and Thurston’s revolutionary ideas will be given. Hamilton’s Ricci flow will be illustrated.

Famously, Perelman turned down both the Clay prize and a Field’s medal for his work.

Cost: Free. RSVP to [email protected]

Groups and Combinatorics Seminar

Cai Heng Li (UWA)

will speak on

Finite meta-primitive permutation groups

at 1pm Tuesday 16th of October in MLR2

Abstract: A transitive permutation group is called meta-primitive if its any imprimitive quotient action is primitive, namely, each of the block systems is maximal. I will discuss the structural properties of meta-primitive groups.

All welcome.

As part of a tradition at the University Physics Screening, fortnightly screenings of various Science Fiction Movies, documentaries and famous recorded lectures will continue screening weekly all through this semester.

This week's screening features the sci-fi classic 'Alien'

FREE ENTRY, and drinks and snacks can be purchased at the door

***NOW RESCHEDULED TO 18 OCTOBER***

“Individual(s) ….embrace a new paradigm for all sorts of reasons ... . Some of these … lie outside the sphere of science entirely. Others depend upon idiosyncrasies of autobiography….” (Kuhn, 1970, p.l52). I will highlight some “idiosyncrasies of autobiography” that have led to enjoying an academic life – the opportunity to research and teach, to construct and communicate knowledge. I plan to illustrate how psychometrics, a field in which I had the opportunity to ignore or embrace an emergent, non-standard statistical paradigm, has lead beyond mathematical modelling to areas such as the philosophy of science, the sociology of knowledge and academic controversy. I plan to also illustrate the challenges in negotiating the complex world of academic research and communication.

Groups and Combinatorics Seminar

Arun Ram (University of Melbourne)

will speak on

Clifford theory and Hecke algebras

at 1pm on Tuesday the 23rd of October in MLR2

Abstract: The usual Clifford theory describes the irreducible representations of group G in terms of those of a normal subgroup. Generalizing, Clifford theory constructs the irreducible representations of semidirect product rings and invariant rings. In this work with Z. Daugherty we use Clifford theory to index the irreducible representations of two pole Hecke algebras and relate this indexing to a labeling coming from statistical mechanics (following work of de Gier and Nichols) and to a geometric labeling (coming from K-theory of Steinberg varieties following Kazhdan-Lusztig). Despite the maths-physics and geometric motivations for the project, in the talk I shall assume only that the audience is familiar with the notions of groups, rings, and modules.

All welcome

UWA, with the Western Australia Mathematical Olympiads Committee, will be hosting the WA Junior Mathematics Olympiad again in 2012, for all bright Year 9 and exceptional Year 8 students. The confirmed date for the 2012 competition is Saturday 3 November 2012.

The Western Australian Integrated Marine Observing System - Annual Science Meeting will present the collaborative and cross-disciplinary uptake of freely accessible coastal and open ocean datastreams. Marine scientists, modellers and engineers, oceanographers and biologists will find this meeting of interest. For any enquiries and registration please contact Agi Gedeon, Manager WAIMOS on [email protected] or x2022.

Groups and Combinatorics Seminar

Wei Jin (UWA)

will speak on

Finite s-Geodesic Transitive Graphs

at 1pm on Tuesday 20th of November in Maths Lecture Room 2

Abstract: A geodesic from a vertex u to a vertex v in a graph is one of the shortest paths from u to v, and this geodesic is called an s-geodesic if the distance between u and v is s.

A graph is said to be s-geodesic transitive if, for each i less than or equal to s, all i-geodesics are equivalent under the group of graph automorphisms. In this talk, I will show the relationship of 2-geodesic transitive graphs with a certain family of partial linear spaces. I will also compare s-geodesic transitivity of graphs with two other well-known transitivity properties, namely s-arc transitivity and s-distance transitivity.

This is a joint work with my supervisors.

All welcome

This course will take you through the basics you need to do statistical analyses in R, a powerful freeware statistical package.

The course will cover basic statistics such as t-tests, regression and ANOVA as well as producing high quality graphics.

The course is hosted by the Centre for Applied Statistics and we offer discounted rate fees to UWA Graduate Research Students.

Fee information is available on our website http://www.cas.maths.uwa.edu.au/courses. Please register online.

Groups and Combinatorics Seminar

Bojan Kuzma (University of Primorska, Slovenia)

will speak on

Graphs and general preservers of zero products

at 1pm on Tuesday 27th of November in MLR2

Abstract: We survey some results in preserver problems where graphs were used as the main tool. In particular, the classification of maps which preserve Jordan orthogonality (AB+BA=0) reduces to the fact that a certain graph is a core and has chromatic number 4. We also give a classification of certain matrices (rank-ones, semisimple, non-derogatory) in terms of a commuting graph.

All welcome.

The course is designed for people with knowledge of basic statistics who want to learn more about designing and analysing experiments.

It will cover material ranging from a review of simple one-way ANOVA, to more complex designs and analyses including crossed and nested factors with fixed and random effects.

The course is hosted by the Centre for Applied Statistics and we offer discounted rate fees to UWA Graduate Research Students.

Fee information is available on our website http://www.cas.maths.uwa.edu.au/courses. Please register online.

SEM is used widely by researchers to test complex relationships among observed (measured) and latent (unobserved) variables. This course will introduce you to SEM and also covers issues relating to model specification, identification and estimation, assessing model fit (goodness-of-fit criteria), and dealing with problem data.

The course is hosted by the Centre for Applied Statistics and we offer discounted rate fees to UWA Graduate Research Students.

Fee information is available on our website http://www.cas.maths.uwa.edu.au/courses. Please register online.

Groups and Combinatorics Seminar

Neil Gillespie (UWA)

will speak on

Completely regular codes with large minimum distance

and

Daniel Hawtin (UWA) will speak on Elusive Codes in Hamming Graphs

at 1pm Tuesday 4th of December in MLR2



Abstracts:

Completely regular codes with large minimum distance: In 1973 Delsarte introduced completely regular codes as a generalisation of perfect codes. Not only are completely regular codes of interest to coding theorists due to their nice regularity properties, but they also characterise certain families of distance regular graphs. Although no complete classification of these codes is known, there have been several attempts to classify various subfamilies. For example, Borges, Rifa and Zinoviev classified all binary non-antipodal completely regular codes. Similarly, in joint work with Praeger, we characterised particular families of completely regular codes by their length and minimum distance, and additionally with Giudici, we also classified a family of completely transitive codes, which are necessarily completely regular. In this work with Praeger, and also with Giudici, the classification given by Borges, Rifa and Zinoviev was critical to the final result. However, recently Rifa and Zinoviev constructed an infinite family of non-antipodal completely regular codes that does not appear in their classification. This, in particular, led to a degree of uncertainty about the results with Praeger and with Giudici. In this talk I demonstrate how I overcame this uncertainty by classifying all binary completely regular codes of length m and minimum distance $ elta$ such that $ elta>m/2$.

Elusive Codes in Hamming Graphs:

We consider a code to be a subset of the vertex set of a Hamming graph. We examine elusive pairs, code-group pairs where the code is not determined by knowledge of its set of neighbours. We provide an infinite family of elusive pairs, where the group in question acts transitively on the set of neighbours of the code. In our examples, we find that the alphabet size always divides the length of the code, and prove that there is no elusive pair for the smallest set of parameters for which this is not the case.

The course is designed as a comprehensive coverage of applied SEM techniques using the Mplus statistical software package. Mplus offers a general modelling framework that allows both the modelling of cross-sectional and longitudinal data using observed variables that are a combination of continuous and categorical variables.

The course is hosted by the Centre for Applied Statistics and we offer discounted rate fees to UWA Graduate Research Students.

Fee information is available on our website http://www.cas.maths.uwa.edu.au/courses. Please register online.

The aim of this course is to introduce you to basic statistics. It will cover descriptive statistics (means and standard deviations); data exploration; basic categorical data analysis; simple linear regression and basic analysis of variance (ANOVA).

Subsidised rates are available for UWA Graduate Research Students.

Please register online.

Enactus UWA is part of an international community of student, academic and business leaders committed to using the power of entrepreneurial action to transform lives and shape a better, more sustainable world.

If you'd like to find out more about what we do, come to this Information Session to learn about our projects, meet the team and find out how you can get involved.