CIRCA

News

Reed–Muller codes and Thomas’ conjecture


There will be a seminar on  Wednesday February 7th, 2018 at 1pm in Lecture Theatre D: Peter Cameron will speak on Reed–Muller codes and Thomas’ conjecture.

Abstract: A countable first-order structure is countably categorical if its automorphism group has only finitely many orbits on n-tuples of points of the structure for all n. (Homogeneous structures over finite relational languages provide examples.) For countably categorical structures, we can regard a reduct of the structure as a closed overgroup of its automorphism group. Simon Thomas showed that the famous countable random graph has just five reducts, and conjectured that any countable homogeneous structure has only finitely many reducts. Many special cases have been worked out but there is no sign of a general proof yet. In order to test the limits of the conjecture, Bertalan Bodor, Csaba Szabo and I showed that a vector space over GF(2) of countable dimension with a distinguished non-zero vector has infinitely many reducts. The proof can most easily be seen using an infinite generalisation of the binary Reed–Muller codes.

CIRCA lunchtime seminars


In the coming semester, CIRCA lunchtime seminars will be on Thursday 1pm in odd weeks in Maths Theatre C (note the change of venue). The first one will be on Thursday, February 1st. Jon Fraser and Shayo Olukoya will be speaking.

CIRCA Lunchtime seminar


The next CIRCA lunchtime seminar will be on Thursday 26th October 2917 at 1pm today in Theatre A of Maths. Nayab Khalid and Mun See Chang will be speaking.

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!

CIRCA Lunches


CIRCA lunches should be resuming shortly. Details will be posted here.

CIRCA Lunch – 19th November 2015


The next CIRCA lunch will take place on Thursday 19th November October at 1-2pm in JC1.33a. The speakers will be Nik Ruskuc and Bilal Hussain.

CIRCA Lunch – 5th November 2015


The next CIRCA lunch will take place on Thursday 5th November at 1-2pm in JC1.33a. The speakers will be Ian Gent and James Hyde.