8th Slovenian Conference on Graph Theory

Last week I was at the 8th Slovenian Conference on Graph Theory.  This was the latest in what is commonly known as the ‘Bled conference’ but this year was in Kranjska Gora. This meant that the conference excursion was to Lake Bled. It was a very enjoyable conference with lots of interesting talks and it was good to catch up with lots of people. I was one of the plenary speakers and my talk was entitled ‘Bounding the number of automorphisms of a graph’. This surveyed the recent work on the Weiss conjecture and its generalisation the PSV conjecture. It also discussed my recent work with Luke Morgan on the PSV conjecture for semiprimitive groups with a nilpotent regular normal subgroup.  More details can be found on my slides.

Symmetries of Graphs and Networks IV

Last week I was at the Symmetries of Graphs and Networks IV conference at Rogla in Slovenia. The conference webpage is here.  At the same time was the annual  PhD summer school in discrete maths. As usual it was a very enjoyable and well organised conference. It was good to catch up with some of the regulars and meet a few new people as well

I was one of the invited speakers and spoke about some of the work that I have been doing recently with Luke Morgan on graph-restrictive permutation groups. The slides are available here.  The two relevant preprints are on the arxiv here and here.

 

 

 

 

Groups, Computation & Geometry at Pingree Park

Last week, I attended an excellent conference “Groups, Computation and Geometry” at the Pingree Park Conference Centre in the Colorado mountains. It was organised magnificently by Peter Brooksbank, Alexander Hulpke, Bill Kantor, Tim Penttila, and James Wilson. Pingree Park is at 9,000 feet (2,700 metres) and I did have headache on the last two days. My trip started badly with a case of gastro, but luckily I had arrived some three days before the conference, so by the second day of talks, I was feeling much better. My 50 minute talk had to be rescheduled to the Friday of the conference, because of this. Apart from your’s truly, the invited talks were given by Colva Roney-Dougal, Şükrü Yalçınkaya, Eric Moorhouse, and Simon Blackburn. Colva spoke about using pregroups to solve problems in combinatorial group theory, mainly word problems, and getting around in a Van Kampen diagram. Şükrü waved the flag for the computational group theorists and spoke on black-box recognition of classical groups. Eric waved the geometry flag and spoke on p-ranks of incidence matrices, and in particular, on ways to attack the “prime-order projective plane implies Desarguesian” conjecture. Simon’s talk carried the main theme of different types of discrete logarithm problems and their application to elliptic curve cryptography. All of these talks were amazing, and I followed each one with keen interest.

Bill Kantor was the master of the schedule, and I was one of only a few that enjoyed the format: only Bill knew who was speaking when, and the program for the subsequent day would be posted on a door each evening. No titles or abstracts, just the expectation that you would see the next talk and you would know then and there what it would be about. It’s good reasoning: if you wanted to know the title and abstract before hand, it might be because you were choosing whether to go or not, and with such a cosy conference, that is out of the question! The other argument, might be that you wanted to do some prior reading before the talk, but would you really?

News Update

It’s been a long time since we posted anything here, but things have kept on happening, so I thought I’d just give a sketchy update.

One of the reasons behind the hiatus in blog posts is that there’s now only two months to go before we host 37ACCMCC, the annual Australasian Combinatorial Conference, here in Perth. I’m the director of the organising committee and it’s quite a juggling act trying to keep on top of everything. It’s a bit of a guessing game too, because we have to book things like the conference dinner and excursion, but with most people registering at the last minute, we have no real idea of numbers! Now I know what it’s like to be on the receiving end, I’m going to register early for all future conferences!

We have a poster now though, which you can see here (or as a PDF here); you can probably recognise the nice building from our blog’s banner image.

A plug/reminder

Just a quick reminder that the annual “Australasian Conference on Combinatorial Mathematics and Combinatorial Computing” (ACCMCC) will be in Perth this December, and registration is open.

It’s a good idea to get in early in getting accommodation at St George’s College (across the road from UWA), which you must book yourself. The early-bird registration is available until 11th November.

For more information, please go to the conference webpage.

37 ACCMCC

This year’s Australasian Conference on Combinatorial Mathematics and Combinatorial Computing will be held here at UWA from the 9th to 13th of December. Put the date in your diary now and start looking for cheap flights to Perth.

The conference webpage is available here, where you can find the exciting lineup of invited speakers that we have lined up so far.

Details of previous conferences in the series are available at the CMSA webpage.

Frank-fest in Ferrara

Following “Combinatorics” in Perugia, was the two-day conference in Ferrara in honour of Frank De Clerck, where I was a co-organiser (with Michel Lavrauw, Jan De Beule, and Nicola Durante). Ferrara is a truly beautiful medieval city and the Castello Estense, where the conference has been held, is the central attraction. All of the lectures were delivered in one of the catacombs of the castle, which made for a cosy atmosphere for the some 50-odd participants.

The calibre of the talks was certainly above average, and I can say for one that I was engaged with most of the material in each lecture. Since Tim Penttila couldn’t make it, I stepped in and gave his talk on Tuesday morning; I couldn’t help but don Tim’s attire and make some bad jokes! The award for the best joke of the conference went to Willem Haemers, where he used the following notation for the 2-rank of a matrix:

-rank

As we are about to leave Ferrara to return to our institutions, we are left with the sentimental closing remarks of Christine O’Keefe and Nicola Durante; our best wishes to Frank for the future!

PS: The PDF’s of the talks will soon appear on the conference webpage.

PPS: I remembered three more things:

1. Simeon Ball and I attended a tango milonga in the Castello Estense on the Sunday evening.
2. I dislocated my thumb during the conference photo shoot.
3. A pizza margherita usually cost 4.50Euro in Ferrara.

Combinatorics in Perugia

This week I’ve been attending the biennial Italian conference “Combinatorics”, which this time, was in the beautiful city of Perugia. For some reason, I was burdened by jet lag for the first 3 days, I must be getting old! There were three parallel sessions and some wonderful invited talks. I will mention only some of the good talks, and I will refrain from chastising some of the poor talks (and there were some). I particularly liked the talks of Geertrui Van de Voorde, Antonio Cossidente, Oli King, Nicola Durante, Jonathan Jedwab, Peter Horak, Qing Xiang, Philippe Cara, Simeon Ball, Ferdinand Ihringer, Olga Polverino, Michel Lavrauw and John Sheekey. On the Wednesday afternoon, we had the choice of two excursions: Assisi or Gubbio, and I went for the former. The tour guide was excellent, she had much to share about her interpretations of the 13th century paintings.

As a constant observer of the price of living in Perth, I am astonished to see that an espresso in central Italy costs 90 Euro cents! (In Perth, you can hardly find an espresso for less than $3.50). I promised Irene Pivotto that I would record proof of this fact on my journey, so here it is:

3rd SYGN Workshop

Last week I was at the 3rd Symmetries of Graphs and Networks Worskhop and PhD Summer School in Discrete Mathematics at Rogla, Slovenia.  The SYGN meeting has been held every two years with the first being at Banff in 2008 and this was the second one held at Rogla. The summer school part continues on the tradition started last year.

Once again the Slovenians did a great job at organising it and it was a very enjoyable conference. I was invited to give a minicourse as part of the summer school on The Polycirculant Conjecture. I have touched on this previously. Boštjan Kuzman kindly took  latex notes of my lectures and these are available at the conference webpage together with the slides from the other courses and talks from the workshop. The other courses were on Graph enumeration by Stephan Wagner and Finite geometries by György Kiss.

Four talks that I found particularly interesting were:

• Roman Nedela’s survey on regular maps. This gave a great overview of the area and I learned a lot about what the main problems in the area are.
• Jozef Siran’s survey on the degree-diameter problem.
• Joy Morris’s talk on the structure of circulant graphs.
• Steve Wilson’s talk on Tales from the census. This is his census with   Primož Potočnik on 4-valent edge-transitive graphs.

Symmetries of Discrete Objects

I am just back from Queenstown, New Zealand where I was attending the Symmetries of Discrete Objects conference.  The conference was well attended with many people from the graph symmetry, maps on surfaces and polytopes communities in attendance.  The conference also served as a Magma workshop with four two lecture mini-courses on aspects to do with Magma. The conference was very well organised by Marston Conder from the University of Auckland and it was announced at the end of the conference that his colleague Dimitri Leemans will organise a sequel in four years time in Nelson.

The conference also won the award for most spectacular view from a lecture room: looking out across Lake Wakatipu to the Remarkables mountain range.

Some talks that I found particularly interesting were:

• Ian Wanless’s on autotopisms of Latin squares
• Tomaz Pisanski’s on GI graphs ( a generalisation of generalised Petersen graphs)
• Steve Wilson’s on Tricirculant edge-transitive tetravalent graphs
• Tom Tucker and Wilfried Imrich’s talks on distinguishability of graphs
• Gabriel Verret’s on his new census of cubic vertex-transitive graphs that I discussed in an earlier post 

I also discovered during Eamonn O’Brien’s Magma course on PC-presentations that Sylow’s famous paper included a forgotten 4th  theorem that essentially states that a p-group has a power-commutator presentation.

I spoke on my recent work on imprimitive rank three groups with Alice Devillers, Cai Heng Li, Geoffrey Pearce and Cheryl Praeger.