# in memoriam Vaughan Jones

It is with great sadness that we learnt of the passing of our colleague and friend, Vaughan Jones, on Sunday 6th September 2020, a few months short of his 68th birthday.

Vaughan was a student in Geneva, first in physics (1974-1976) then in mathematics (1976-1980), and he completed his doctorate under the supervision of André Haefliger in 1979. Since then he was a regular visitor to Geneva, influencing so many people through seminars and informal discussions. He was due to return again in November as an invited speaker for the Wright Colloquium. During many years, he taught so much mathematics to his students, his colleagues and his own teachers. With a great sense of humour, he exuded enthusiasm and generosity, be it about his love of mathematics, music or sport - all in his unique down-to-earth style.

In May 2019, Wendy and Vaughan celebrated 40 years of marriage in Geneva, the city where they first met.

Vaughan Jones was born in Gisborne, New Zealand, on December 31, 1952. After his studies, first in Auckland, then in Geneva, he held appointments at a number of universities in the US (Los Angeles, Philadelphia, Berkeley and Vanderbildt) along with a position at the University of Auckland. His mathematical discoveries were recognised by the awarding in 1990 of a Fields Medal - the highest distinction in mathematics (along with the Abel Prize). He also received the Nessim Habif Prize at the Dies Academicus 2007 in Geneva, as well as many other prestigious awards and honours.

His mathematical work had a profound impact on a number of fields, including topology, functional analysis and mathematical physics. In 1984 he discovered a remarkable connection between von Neumann algebras and knot theory. This allowed him to define a new invariant of knots which now bears his name, the Jones polynomial, which has become one of the fundamental objects in knot theory. Other important contributions include the study of knot invariants using ideas coming from statistical physics, results about quantum groups and their representations, and the invention and development of the theory of planar algebras. More recently Vaughan initiated a programme to connect knot theory with Thompson's group, an idea currently attracting considerable interest.

10 January 2020