Welcome to the Heather Cafe
I’m Chris Jefferson, a professor at the University of St Andrews and University of Dundee, currently based at the Dundee International Institute at Central South University in Changsha, China.
Research interests
My work spans three main areas (see the full publications list for details):
- Computational group theory — algorithms for permutation groups, particularly graph backtracking, canonical images, and refiners. I develop the Vole and GraphBacktracking packages for GAP, and I’m writing a set of notes on permutation group algorithms.
- Constraint programming — solver design, propagation algorithms, and automated modelling. I’m one of the authors of the Minion constraint solver and the Essence specification language.
- Puzzles and games — puzzle generation, difficulty measurement, and understanding how humans solve puzzles. The Demystify tool explains puzzle solutions step by step.
I also work on symmetry breaking in constraint models and combinatorics/algebra problems where computational methods help.
Prospective PhD students
I welcome applications from students interested in doing a PhD in any of the areas above. If you’d like to get in touch, please email me at caj21@st-andrews.ac.uk and mention that you found this page at heather.cafe — I get a very large number of generic emails about PhD positions, and this helps me know you’ve actually looked at my work.