Availability

Subject to my existing commitments: I am always keen to hear from applicants with a strong background in functional analysis. Some previous exposure to representation theory of groups or the general theory of (matrix) Lie groups would be desirable, but is not essential.

Current ideas for PhD projects

Here are four possible areas in which I am willing to supervise: each of these is not a specific PhD project, but a setting in which there are various possible research problems that a student could work on. If you would like to know more, then please feel free to get in touch.

1. Ulam stability for Banach and operator algebras
2. Banach algebras associated to group actions on L^p spaces
3. Fourier algebras of locally compact groups
4. Non-selfadjoint subalgebras of Type I C*-algebras

Warning notes.

Themes 3 and 4 will require a student to start by learning the basic theory of C*-algebras, before getting on to the actual PhD project(s). C*-algebra theory is also valuable context for Themes 1 and 2, but in those cases there are "sub-projects" where one can get started on research without pre-existing C*-background.

It is possible that you are reading this and have had some exposure to various structural properties of Banach algebras known as "approximate amenability", "character amenability", or "module amenability". I will not, for the foreseeable future, supervise on any of these three, nor on any hybrid of these.

See https://www.maths.lancs.ac.uk/~choiy1/pubmath/papers.html for my papers.

The keyword version

Banach and operator algebras. Noncommutative harmonic analysis. Categorical and homological perspectives on functional analysis.

The longer version

I am interested in a range of topics and problems on the interface between algebra and functional analysis. This tends to be driven by particular families of examples, but my preference is for finding general frameworks that unify common features of these examples, once one has investigated individual examples in depth.

In recent years I have worked intensively on various aspects of the Fourier algebras of locally compact groups: studying these objects involves a blend of (non-commutative) harmonic analysis and representation theory. Many of the developments over the last 20 years or so use the tools, or are guided by the philosophy, of the theory of operator spaces and completely bounded maps -- these may be thought of as enriched versions of Banach spaces and linear maps between them, where one allows matricial coefficients and not just scalar ones.

I am also interested in algebras of convolution operators arising from the canonical representation(s) of a group G on the Banach space L^p(G). When p=2 there is a rich theory available, from the world of C*-algebras and von Neumann algebras; for other values of p many basic structural questions remain unresolved, even for very explicit examples such as G=SL_n(R) or SL_n(Z).

http://www.maths.lancs.ac.uk/~choiy1/

Departmental Director of Studies for students on joint degree schemes (non-LUMS)

Departmental Director of Studies for Study Abroad students

Departmental contact/representative for Natural Sciences degree programme

Mahmood Alaghmandan, 2013. (Supervised at the University of Saskatchewan, Canada, joint with E. Samei)

Bence Horvath, 2019. (Joint with N. J. Laustsen)

Christopher Menez, 2019.

M. Eugenia Celorrio, 2023. (Joint with H. G. Dales)

Aug. 2022 - present: Senior Lecturer, Lancaster University, United Kingdom

Jan. 2014 - Jul. 2022: Lecturer, Lancaster University, United Kingdom

Aug. 2010 - Jan. 2014: Assistant Professor (tenure-track), University of Saskatchewan, Canada

Aug. 2008 - Jul. 2010: Postdoctoral researcher, Universite Laval, Canada

Feb. 2007 - Jul. 2008: Postdoctoral fellow, University of Manitoba, Canada

Sept. 2002 - Jun. 2006: PhD student, University of Newcastle upon Tyne, United Kingdom

Sept. 2001 - Jun, 2002: Editorial assistant, National Extension College, United Kingdom.

B.A. in Mathematics (2000, Cambridge).

CASM (2001, Cambridge).

PhD in Pure Mathematics (2006, Newcastle-upon-Tyne)

External examiner

S. Trotter (Leeds, PhD, 2016)

Y. Ji (Newcastle, PhD, 2018)

Internal examiner

E. Kastis (PhD, Lancaster, 2017)

T. Gaudio (PhD, Lancaster, 2021)