Draft:Leonard Soicher

Leonard Soicher
Soicher in May 2026
Born	1955 (age 70–71) Canada
Education	Concordia University (BSc, MCompSci) University of Cambridge (PhD)
Scientific career
Fields	Group theory Algebraic graph theory Design theory Computational mathematics
Institutions	Queen Mary University of London
Doctoral advisor	John H. Conway
Website	webspace.maths.qmul.ac.uk/l.h.soicher

Leonard Hyman Soicher is a British-Canadian mathematician who is known for his work in algebraic graph theory, group theory, combinatorial design theory, and discrete computational mathematics. He is an Emeritus Professor of Mathematics at Queen Mary University of London.^[1]

Education

Soicher earned a BSc in mathematics in 1978 and a Master of Computer Science in 1981^[2], both from Concordia University in Montreal, Canada. His master's thesis was titled “The Computation of Galois groups” and was supervised by John McKay.^[3] He won a Commonwealth Scholarship^[4] to pursue a doctorate from the University of Cambridge, with John H. Conway as his supervisor.^[5] Soicher was awarded his PhD in 1985, with a PhD thesis being titled “Presentations of Some Finite Groups”^[6] that focused on sporadic simple groups.

Career

Soicher has worked across a range of fields as a professional pure mathematician. After finishing his doctorate, he worked again with John McKay as a postdoc at Concordia University in Canada.^[7] He then joined Queen Mary University of London in 1987, where he remained until retirement in 2018, achieving promotion to Professor in 2007.^[8]

Soicher is most known for his early work on presentations of sporadic simple groups; his contribution to the ATLAS of Finite Groups; the Bimonster group; his work with Charles Leedham-Green developing “collection from the left”^[9] and the product replacement algorithm^[10][11] in computational group theory; his research on distance-regular graphs (especially the three so-called Soicher graphs^[12][13] and the Moscow-Soicher graph^[14][15]); and his long-term and ongoing authorship and development of the GRAPE package^[16] for GAP. Soicher is also a co-creator and maintainer of the website designtheory.org.

During his career, Soicher has collaborated and published joint work with numerous notable mathematicians, including Peter Cameron, John Conway, Simon P. Norton, Cheryl Praeger, and Sarah Rees (professor)^[17].

GAP

Soicher has been a member of the council of the computer algebra system GAP since June 1997, and was its chair from March 2009 until September 2021.^[18] He is the author of the GRAPE^[19] and DESIGN^[20] packages for GAP. A special session in honour of Soicher's 70th birthday was held at the GAP Days Summer 2025 workshop in Koper, Slovenia.^[21]

Selected publications

• with John McKay: Computing Galois groups over the rationals, Journal of Number Theory (1985).
• with John H. Conway, Simon P. Norton: The Bimonster, the group Y₅₅₅, and the projective plane of order 3, Computers in Algebra (1988).
• with Rosemary A. Bailey, Peter J. Cameron, Peter Dobcsányi, John P. Morgan: Designs on the web, Discrete Mathematics (2006).
• with Cheryl E. Praeger: Low rank representations and graphs for sporadic groups, Cambridge University Press (1996).

References

Category:Living people Category:Academics of Queen Mary University of London Category:Alumni of the University of Cambridge Category:20th-century Canadian mathematicians Category:21st-century Canadian mathematicians Category:Group theoristsCategory:Combinatorialists Category:Year of birth missing (living people) Category:Place of birth missing (living people)