Sarah Rees


School of Mathematics, Statistics and Physics
University of Newcastle
Newcastle NE1 7RU
UK
 
+44 (191) 208 7236 
Fax:  +44 (191) 208 8020 
Email: 
Sarah(DOT)Rees@ncl(DOT)ac(DOT)uk 

Office hours for Newcastle students
Normally I have regular office hours in term time for students in the modules
I lead,
when I am happy to see students without appointment, in my office 3.07 (Herschel building).
If I cannot manage one of my office hours I will notify students with a notice on my door and via this webpage.
Students who cannot manage my office hours may email me
for appointments.
In semester 2 2017,18, I don't think regular office hours in the Herschel
building, far away from the new computing science building,
make sense for the students of MAS8401; so could those students email me
if they'd like to meet 1on1, or ask me about this when we meet for our
our lectures?
Research Interests
I work mainly on geometrical, combinatorial and computational aspects of
group theory. In particular I am currently interested in
 decision problems,
 links between group theory and formal language theory,
 the theory of automatic groups and group combings,
 the language theoretical complexity of the word problem,
 the theoretical and practical development of algorithms in group theory.
My book
My book,
Groups Languages and Automata, authors
Derek F. Holt, Sarah Rees, Claas E. Röver, was published by CUP in February 2017, as volume 88 of the London Mathematical Society student texts series.
We three authors are maintaining a list of errors and misprints in our book as we discover them; so please let one of us know (e.g. by email) if you find any problems that are not in that list.
Electronic copies of articles from 1998 onwards
 Laura Ciobanu, Derek Holt, and Sarah Rees,
Equations in groups that are virtually direct products
 Patrick Dehornoy, Derek F. Holt and Sarah Rees,
Multifraction reduction IV:
Padding and ArtinTits monoids of sufficiently large type
, to appear in J. Pure and Applied Algebra.
 Gabriele Nebe, Richard Parker and Sarah Rees,
A method for building permutation representations of finitely presented groups, in Proceedings of Finite Simple Groups: Thirty Years of the Atlas and Beyond, Princeton 2015.
 Derek F. Holt and Sarah Rees,
Some closure results for Capproximable groups, Pac. J. Math. 2872 (2017) 393409.
 Eddy Godelle and Sarah Rees,
Rewriting systems in sufficiently large ArtinTits groups, J. Alg. 466 (2016) 284307.
 Laura Ciobanu, Derek Holt, and Sarah Rees,
The generalised word problem in hyperbolic and relatively hyperbolic groups
 Laura Ciobanu, Derek Holt and Sarah Rees,
Rapid decay and BaumConnes for large type Artin groups, TAMS 368 (2016) 61036129.
 My review of the film The Imitation Game, which appeared in the Newsletter of the Association for Women in Mathematics (AWM), MarchApril 2015, 1719.
 Laura Ciobanu, Susan Hermiller, Derek Holt, and Sarah Rees,
Conjugacy languages in groups, Israel J. Math. 211 (2015) 311347.
 Derek F. Holt and Sarah Rees,
Conjugacy in Artin groups of extralarge type, J. Alg. 434 (2015) 1226.
 Laura Ciobanu, Derek Holt and Sarah Rees,
Sofic groups: graph products and graphs of groups, Pac. J. Math. 271 (2014) 5364.
 Mark Lawson, Liam O'Carroll and Sarah Rees,
David Rees 19182013,
Semigroup Forum 88 (2014) 513522.
 Derek F. Holt and Sarah Rees,
Shortlex automaticity and geodesic regularity in Artin groups,
Groups, Complexity and Cryptology 5 (2013) 123.
 Laura Ciobanu, Derek F. Holt and Sarah Rees,
Rapid Decay is Preserved by Graph Products,
Journal of Topology and Analysis 5 (2013) 225237.
 Derek F. Holt and Sarah Rees,
Generalising some results about rightangled Artin groups to graph products of groups,
Journal of Algebra 371 (2012) 94104.
 Derek F. Holt and Sarah Rees,
Artin groups of large type are shortlex automatic with regular geodesics,
Proc. London Math. Soc 104 (2012) 486512.
 Derek F. Holt, Sarah Rees, Claas E. Röver,
Groups with ContextFree Conjugacy Problems,
Int. J. Alg. Comput. 21 (2011) 193216.
 Derek F. Holt, Sarah Rees and Michael Shapiro,
Groups that do and do not have growing contextsensitive word problem,
Int. J. Alg. Comput. 18 (2008) 11791191.
 Susan Hermiller, Derek Holt and Sarah Rees,
Groups whose geodesics are locally testable,
Int. J. Alg. Comput. 18 (2008) 911923.
 Robert H. Gilman, Susan Hermiller, Derek F. Holt and Sarah Rees,
A characterisation of virtually free groups,
Archiv der Math. 89 (2007) 289295
 Sarah Rees,
The automata that define representations of monomial algebras,
Algebras and Representation Theory 11 (2008) 207214.
 Oliver Payne and Sarah Rees,
Computing subgroup presentations using
the coherence arguments of McCammond and Wise,
J. Alg. 300 (2006) 109133
(LeedhamGreen birthday volume).
 Susan Hermiller, Derek Holt and Sarah Rees,
Starfree geodesic languages for groups,
Int. J. Alg. Comp. 17 (2007) 329345.
 Michael Batty, Sam Braunstein, Andrew Duncan and Sarah Rees,
Quantum algorithms in group theory,
Computational and experimental group theory, 162, Contemp. Math., 349, Amer. Math. Soc., Providence, RI, 2004
 Derek F. Holt, Sarah E. Rees, Claas E Röver, and Richard M. Thomas,
Groups with contextfree coword problem,
Journal of the London Mathematical Society 71 (2005) 643 657.
 Sarah Rees,
How hard is the word problem?,
in Proceedings of Conference for European Women in Mathematics, Varna, Bulgaria, September 2002.
 Derek F. Holt and Sarah Rees,
Regularity of quasigeodesics in a
hyperbolic group,,
Internat. J. Alg. Comp. 13 (2003) 585596.
 Derek F. Holt and Sarah Rees,
Solving the word problem in real time,
J. London Math. Soc. 63 (2001), 623639.
 George Havas, Derek F. Holt, P.E.Kenne and Sarah Rees,
Some challenging group presentations,
J. Austral. Math. Soc. 67 (1999) 137163.
 Sarah Rees and Leonard H. Soicher,
An algorithmic approach to fundamental groups and
covers of combinatorial cell complexes,
Symb. J. Comput. 29 (2000) 5977.
 Robert H. Gilman, Derek F. Holt and Sarah Rees,
Combing nilpotent and polycyclic groups,
Inter. J. Alg. Comput. 9 (1999) 135155.
 Derek F. Holt and Sarah Rees,
Computing with abelian sections of finitely presented groups,
J. Algebra 214 (1999) 714728.
 Sarah Rees,
Hairdressing in groups: a survey of combings and formal languages,
Geometry and Topology Monographs 1 (1998),
The Epstein Birthday Schrift, paper no. 24, pages 493509.
 Sarah Rees,
A language theoretic analysis of combings,
Contemp. Math. 250, 117136
 Sarah Rees,
Automatic groups associated with word orders other than shortlex,
Inter. J. Alg. Comput. 8 (1998), 575598.
Computer packages
 quotpic,
an interactive graphics
package to compute and display quotients of a finitely present group,
and testisom, which attempts to test for isomorphism
between two finitely presented groups,
both developed jointly with Derek Holt, and
available from the Warwick mathematics
ftparchive.
as a joint package isom_quotpic.
 automata,
a suite of programs, developed with David Epstein
and Derek Holt, to constructively
verify that a finitely presented group is shortlex automatic. Now superceded
by Derek Holt's kbmag package, which is available from the
Warwick mathematics
ftparchive.
and contains my own code to test for automaticity with respect to
other word orders than shortlex.
 matrix group algorithms developed jointly with
Derek Holt, Charles LeedhamGreen and Eamonn O'Brien, and now part of
the matrix package within the
GAP system

I have contributed to the magnus system,
developed by the
New York Group Theory Cooperative
Useful links
within Newcastle:
(some of these are really for my personal use,
others are for students)
 my link (with password access) to blackboard in Newcastle;
all my material for my lecture courses is available here.
 my link to Newcastle University library. The search facility in on this page, and from that I have password access
to MathSciNet, JCR, and journals to which Newcastle has electronic access.
 information about postgraduate study in Newcastle. Potential applicants
should look at this. There's a link to the online application system.
 my personal link to Ness
(student marks), which has access only
by password
 Newcastle's Remote application Service
 Password access to Newcastle's MyImpact system
 School of Maths and Stats Resources for Staff
 School Calendars
 A record of School Staff Leave
 the Newcastle forms to be filled out when I am away on business
 certain Newcastle web requisition system forms (that is, the ones relating to travel; these should cover everything I need to book).
 Password access to Newcastle's MyApps system
 Password access to Newcastle's MyProjects system
 the maths and stats wiki,
which also has access only by password
 Newcastle myworkplace,
useful for expenses claims,
which also has access only by password
 classlists for courses at Newcastle,
(access only by password)
 secure entry to the
the outlook email service in Newcastle.
 results of student questionnaires at Newcastle,
 the Newcastle lunch run.
and outside Newcastle: