Research interests:

Enveloping Algebras, Quantum Groups and Invariant Theory.


Quantum groups and their primitive ideals, Springer, Berlin 1995.

Recent Talks:

MIT Kostant Memorial Conference [link]

Recent publications:



Orbits, Primitive Ideals and Quantum Groups  (conference videos)

Bar Sagi Tiling

     This is a family of proper self-similar triangle tilings dedicated to the memory of Bar Sagi who died on 26 February 2017 at age 15 after a long, painful and terrifying ordeal with bone cancer.  Her book of poems published posthumously was deemed by Professor Carlos Cardas, a leading oncologist at Cambridge University, as “mandatory reading for any aspiring cancer doctor”. 
       Bar Sagi tiling was motivated partly out of trying to represent weight diagrams in the plane. It became a game for my grand-daughter Bar when she was six years old.  After her death I made substantial additions and dedicated a paper to appear in Progress in Mathematics (see publications) to her memory.
       Bar Sagi tiling cannot always be two-coloured though it is plausible that it can always be three-coloured.  Finding an aesthetically pleasing colouring is not so easy.  The reader is invited to try from the examples given below using Paint 3D.