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Picture  of Gwyneth Stallard

Prf Gwyneth Stallard

Professor Of Pure Mathematics

School of Mathematics & Statistics

gwyneth.stallard@open.ac.uk

Biography

Professional biography

I am currently the university's academic lead for Athena Swan, and Deputy Head of School with a particular interest in supporting the career development of staff. 

Advancing women's careers in mathematics

I have a long standing interest in the issues surrounding women's careers in mathematics and chaired the London Mathematical Society's (LMS) Women in Mathematics Committee from 2006 to 2015. This work was recognized by the award of an OBE in 2015.  Details of the work carried out by the LMS to support women's careers can be found here http://www.lms.ac.uk/women-mathematics. I was also a Diversity Champion on the EPSRC Mathematical Sciences SAT. I chaired the School's Athena SWAN self assessment team from 2013 to 2022 - we were awarded a Bronze award in 2014, which was renewed in 2017, and were awarded a Silver award in 2022.

Research interests

My research is in the area of complex dynamics and concerns the iteration of transcendental meromorphic functions. I am particularly interested in the possible dimensions of the Julia set, the structure of the escaping set and the behaviour of wandering domains.

Together with Professor Phil Rippon, I lead the complex dynamics group at the OU which is part of the rapidly growing dynamical systems group which has a regular seminar series.

The group includes Vasso Evdoridou (Lecturer) together with various PhD students and our activities often include other complex analysts in the department.

Phil Rippon and myself have received several grants from EPSRC, with the most recent funding a project to classify the behaviour in simply connected wandering domains. Together with Vasso, we continue to build on this work in collaboration with Nuria Fagella (University of Barcelona) and Anna Miriam Benini (University of Parma). 

We were previously funded by EPSRC to investigate a surprising link that we identified between two open conjectures in complex dynamics: Baker's conjecture and Eremenko's conjecture. The work was funded by two grants which together funded our work for five years (0.5FTE each). More details on the project are given here:

  • EP/H006591/1: Baker's conjecture and Eremenko's conjecture: a unified approach
  • EP/K031163/1: Baker's conjecture and Eremenko's conjecture: new directions

Our former Research Associate, Dave Sixsmith, was funded by the following grant from the EPSRC:

  • EP/J022160/1: Dimensions in complex dynamics: spiders' webs and speed of escape

Teaching interests

Most of my teaching has been in the area of analysis. I am currently deputy chair for M208 Pure Mathematics and am responsible for the MSc course M835 Fractal Geometry.

Projects

Baker's conjecture and Eremenko's conjecture: a unified approach (XM-08-066-GS)

Complex dynamics studies the iteration of analytic functions, to understand the structure of the Fatou set F(f) (stable set) and the Julia set J(f) (chaotic set). The escaping set I(f) consists of the points that iterate to infinity. Eremenko showed that I(f) is closely related to J(f), and asked key questions about it. As a result many authors have studied I(f), with major breakthroughs in recent years, many by the applicants. In 2007/8, we found key new techniques that should give much deeper understanding of the intricate structure of I(f). This application is to fund our time to achieve this.

Classifying Wandering Domains

The main aim of the proposed research is to complete the classification of the types of dynamical behaviour that can occur within the components of the Fatou set (the set of stability) arising in the iteration of analytic functions. There is a large historical body of work classifying the dynamical behaviour within periodic Fatou components and a recent paper gives a complete description of the behaviour in multiply connected wandering domains. This project will address the outstanding case of simply connected wandering domains. There are many different types of dynamical behaviour within such domains and they have not previously been studied systematically. The development of a unifying theory will be fundamental to future work on iteration. The theory will be illustrated and informed by the construction of new examples of wandering domains.

Publications

Journal Article

Boundary dynamics for holomorphic sequences, non-autonomous dynamical systems and wandering domains (2024)

Oscillating simply connected wandering domains (2022)

Classifying simply connected wandering domains (2022)

Iterating the minimum modulus: functions of order half, minimal type (2021)

On Subharmonic and Entire Functions of Small Order: After Kjellberg (2021)

Eremenko's Conjecture for Functions with Real Zeros: The Role of the Minimum Modulus (2021)

The iterated minimum modulus and conjectures of Baker and Eremenko (2019)

Eremenko points and the structure of the escaping set (2019)

Baker's conjecture for functions with real zeros (2018)

Boundaries of univalent Baker domains (2018)

Connectedness properties of the set where the iterates of an entire function are unbounded (2017)

Permutable entire functions and multiply connected wandering domains (2016)

Annular itineraries for entire functions (2015)

Regularity and fast escaping points of entire functions (2014)

A sharp growth condition for a fast escaping spider’s web (2013)

Multiply connected wandering domains of entire functions (2013)

Fast escaping points of entire functions (2012)

Baker's conjecture and Eremenko's conjecture for functions with negative zeros (2012)

Boundaries of escaping Fatou components (2011)

Slow escaping points of meromorphic functions (2011)

Hausdorff dimensions of escaping sets of transcendental entire functions (2010)

Are Devaney hairs fast escaping? (2010)

The growth rate of an entire function and the Hausdorff dimension of its Julia set (2009)

Functions of small growth with no unbounded Fatou components (2009)

Escaping points of entire functions of small growth (2009)

On multiply connected wandering domains of meromorphic functions (2008)

Dynamics of meromorphic functions with direct or logarithmic singularities (2008)

Dimensions of Julia sets of meromorphic functions with finitely many poles (2006)

Singularities of meromorphic functions with Baker domains (2006)

Escaping points of meromorphic functions with a finite number of poles (2005)

Dimensions of Julia sets of meromorphic functions (2005)

On questions of Fatou and Eremenko (2005)

Dimensions of Julia sets of hyperbolic entire functions (2004)

Dimensions of Julia sets of hyperbolic meromorphic functions (2001)