Dr John M Mackay

BSc(Edin.), PhD(Mich.)

  • BS8 1UG


Research output per year

If you made any changes in Pure these will be visible here soon.

Personal profile

Research interests

Geometric group theory, particularly hyperbolic and relatively hyperbolic groups.  

Analysis on metric spaces, especially questions related to Hausdorff dimension and quasisymmetric maps.

Ph.D. projects

The two main themes of my research are geometric group theory and analysis on metric spaces.

Geometric group theory involves the study of infinite, finitely generated groups by considering how they act on appropriate spaces.  I am particularly interested in Gromov’s hyperbolic groups, and how they can be studied using their “boundary at infinity”.  (For example, three dimensional hyperbolic space, in the Poincaré ball model, has a natural sphere at infinity.)  These boundaries are metric spaces, usually fractal, and may carry a rich analytic structure.  The key question is to relate the algebraic properties of such groups with the analytic properties of their boundaries.  Interesting examples of hyperbolic groups include Gromov’s “random groups” and many examples from low dimensional topology.

I am particularly interested in the conformal dimension of the boundary.  This is a variation on Hausdorff dimension due to Pansu.  There are many spaces of interest where this dimension is not known, or even well estimated.  Conformal dimension links to my other main interest, analysis on metric spaces.  This involves the study of (non-smooth) functions on metric spaces that have no given smooth structure, but satisfy some weaker conditions.  This is motivated first by applications where the spaces that arise have only weak regularity.  A second motivation arises from the desire to understand classical results better by finding out exactly what hypotheses they require.

If you are interested in discussing potential projects in these areas, please do contact me. For more information, see my webpage:

http://www.maths.bris.ac.uk/ ̃jm13806/

Fingerprint Dive into the research topics where John M Mackay is active. These topic labels come from the works of this person. Together they form a unique fingerprint.

  • 1 Similar Profiles

Network Recent external collaboration on country level. Dive into details by clicking on the dots.


Research Output

  • 17 Article (Academic Journal)
  • 1 Authored book
  • 1 Other contribution

Poincaré profiles of groups and spaces

Hume, D., Mackay, J. M. & Tessera, R., 2 Mar 2020, In : Revista Matemática Iberoamericana. 36, 6, p. 1835-1886 52 p.

Research output: Contribution to journalArticle (Academic Journal)

Open Access
  • 34 Downloads (Pure)

    Poorly connected groups

    Hume, D. & Mackay, J. M., 13 Apr 2020, (Accepted/In press) In : Proceedings of the American Mathematical Society.

    Research output: Contribution to journalArticle (Academic Journal)

  • Random triangular Burnside groups

    Mackay, J. M. & Gruber, D., 22 Jun 2020, (Accepted/In press) In : Israel Journal of Mathematics.

    Research output: Contribution to journalArticle (Academic Journal)


    • 4 Participation in conference

    IPAM Workshop on non-smooth geometry

    John M Mackay (Invited speaker)

    1 May 2013

    Activity: Participating in or organising an event typesParticipation in conference

    Young Geometric Group Theory II

    John M Mackay (Invited speaker)

    5 Feb 2013

    Activity: Participating in or organising an event typesParticipation in conference

    Potential theory and its related fields

    John M Mackay (Invited speaker)

    6 Sep 2012

    Activity: Participating in or organising an event typesParticipation in conference