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n-Queens Completion is NP-Complete


Ian Gent, Chris Jefferson and Peter Nightingale have shown that the n-Queens puzzle (given a chessboard of size n x n, place n queens so that no two queens attack each other) is NP-Complete. Their paper “Complexity of n-Queens Completion” was published in the Journal of Artificial Intelligence Research on August 30. See these two articles: “Simple” chess puzzle holds key to $1m prize and n-Queens Completion is NP-Complete for further details.

Groups St Andrews 2017 in Birmingham


Groups St Andrews 2017 in Birmingham took place on August 5th-13th. This is the tenth in the series of Groups St Andrews Conferences which have been held every four years from 1981. The main speakers were Michael Aschbacher (Caltech), Pierre-Emmanuel Caprace (Université Catholique de Louvain), Radha Kessar (City, University of London) and Gunter Malle (TU Kaiserlautern). One hour speakers were Tim Burness (Bristol), Vincent Guirardel (Université de Rennes 1), Harald Helfgott (Göttingen), Andrei Jaikin-Zapirain (Universidad Autónoma de Madrid) and Donna Testerman (École Polytechnique Fédérale de Lausanne). The organisers are Colin Campbell, Martyn Quick, Edmund Robertson and Colva Roney-Dougal together with Chris Parker from Birmingham.

The conference has been followed by a satellite event – a tutorial on the computational algebra system GAP on August 13th-14th. It has been organised by Alexander Konovalov together with Sergey Shpectorov from Birmingham. On Sunday Alexander Konovalov taught the Software Carpentry lesson “Programming with GAP”, and on Monday Markus Pfeiffer explained various aspects of using GAP effectively and demonstrated the GAP Jupyter interface being developed in the OpenDreamKit project.

 

All kinds of mathematics


A conference “All Kinds of Mathematics Remind me of You” to celebrate the 70th Anniversary of Peter Cameron took place in Lisbon on 24-27 July 2017. It was followed by a one-day workshop “Symmetry in Finite and Infinite Structures“. Both events took place at the University of Lisbon and were organised by mathematicians from Universidade Aberta and the Universities of Aveiro, Coimbra and Lisbon, led by João Araújo.

Quoting the School newsletter, participants ranged in academic age from Peter’s own DPhil supervisor Peter Neumann to recent St Andrews undergraduate Scott Harper. They included more than twenty co-authors including three with nine or more joint publications with him. The other participants from St Andrews were Rosemary Bailey (who spoke on “Circular designs with weak neighbour balance”), Collin Bleak, Julius Jonusas (“Universal words and sequences”), James Mitchell (“Semigroups from digraphs”), Shayo Olukoya (“Growth rates of automata groups generated by reset automaton”) and Wilf Wilson (“Maximal subsemigroups of monoids of partial order-(anti)endomorphisms”).

The final talk has been given by Peter himself and was entitled “Perchance to dream …”. It mentioned several outstanding problems, and Peter hopes that participants will solve many of these before the next conference!

In a series of five blog posts, Peter gave a detailed account of each day: see those for day 1, day 2, day 3, day 4 and the workshop.

Peter Cameron awarded the 2017 LMS Senior Whitehead Prize


Congratulations to Peter Cameron on being awarded the 2017 Senior Whitehead Prize of the London Mathematical Society! The prize is awarded for ‘exceptional research contributions across combinatorics and group theory, his fertile imagination and encouragement of others having sparked activity in many fields’. He became the third person to win both a Junior and Senior Whitehead Prize. Please read further details in the LMS announcement and in this post in Peter Cameron’s blog.

NBSAN meeting in St Andrews


On July 13th, we hosted the meeting of NBSAN (North British Semigroups and Applications Network). It was organised by Julius Jonusas, and the speakers were Nick Gilbert, Zur Izhakian, Mark Kambites, Matt McDevitt and Munazza Naz. Slides of some talks from the meeting are available on the NBSAN website.

Visits and conferences – May 2017


  • The London Combinatorics Colloquia took place at Queen Mary University of London on 10th May, when Sophie Huczynska gave a talk “Graph classes under homomorphic image order”, and the following day at the London School of Economics. Whilst there Peter Cameron chaired a meeting of the British Combinatorial Committee, also attended by Nik Ruskuc.
  • Nik Ruskuc visited Robert Brignall at the Open University for a week to pursue their joint research project about the property of well quasi order in combinatorics.
  • Colin Campbell, Edmund Robertson and Nayab Khalid attended the 40th Groups in Galway meeting at NUI Galway from 18-20th May.

Semigroups 3.0 Hackathon


It’s been a long time coming, but Semigroups 3.0 is nearly ready for release.  We’re going to have a hackathon to squash all the remaining bugs, add documentation, replace TODOs, and generally polish and tweak the package until it’s ready to be released! The kick-off is at 11am on Monday May 29th in Maths Lecture Theatre D. Everyone is welcome to join!

Groups St Andrews 2017 in Birmingham


Groups St Andrews 2017 takes place in Birmingham on August 5th-13th 2017. The talks will happen from 6th August until 12th August 2017 (inclusive). It will be followed by a satellite event – a tutorial on the computational algebra system GAP on August 13th-14th.

 

Notes on Counting


Peter Cameron’s book “Notes on Counting: An Introduction to Enumerative Combinatorics” should be published by Cambridge University Press in June 2017, as part of the Australian Mathematical Society Lecture Series. For further details, see Peter Cameron’s blog.

Third Scottish Combinatorics Meeting


The Third Scottish Combinatorics Meeting on 24-25th April was hosted by Sophie Huczynska and Nik Ruskuc. Rosemary Bailey was one of the invited speakers and Matt McDevitt also gave a talk. Other invited speakers included Robert Brignall, who gained his PhD in St Andrews PhD in 2007 and who now works at the Open University, as well as being our Subhonours External Examiner. Following the meeting, Robert stayed from 26-28th April to collaborate with Nik on well quasi ordered-ness of pattern classes of permutations. Another invited speaker, Maura Paterson from Birkbeck, University of London also stayed from 26-28th April to work with Sophie on external difference families and related topics.