Top Posts
Recent comments
- Jon Awbrey on Mathematical diversity
- Peter Cameron on Mathematical diversity
- Peter Cameron on Finite geometry in Brighton
- jgilbey2014 on All kinds of mathematics, 1
- José Manuel Dos Santos Dos Santis on All kinds of mathematics, 1
Blogroll
- Alexander Konovalov
- Annoying precision
- Astronomy Picture of the Day
- Azimuth
- Bad science
- Bob Walters
- British Combinatorial Committee
- CIRCA tweets digest
- CoDiMa
- Coffee, love, and matrix algebra
- Comfortably numbered
- Computational semigroup theory
- DC's Improbable Science
- Diamond Geezer
- Exploring East London
- From hill to sea
- Gödel's lost letter and P=NP
- Gil Kalai
- Haris Aziz
- Intersections
- Jane's London
- Jon Awbrey
- LMS blogs page
- Log24
- London Algebra Colloquium
- London Reconnections
- Marie Cameron's blog
- MathBlogging
- Micromath
- Neill Cameron
- neverendingbooks
- Noncommutative geometry
- numericana hall of fame
- Paul Goldberg
- Robert A. Wilson's blog
- Sheila's blog
- Since it is not …
- Spitalfields life
- St Albans midweek lunch
- Stubborn mule
- Sylvy's mathsy blog
- SymOmega
- Tangential thoughts
- Terry Tao
- The Aperiodical
- The De Morgan Journal
- The ICA
- The London column
- The Lumber Room
- The matroid union
- Theorem of the day
- Tim Gowers
- Vynmath
- XKCD
Find me on the web
Cameron Counts: RSS feeds
Meta
Category Archives: open problems
A small fact about the Petersen graph
The Petersen graph has 10 vertices and 15 edges, and the complete graph on 10 vertices has 45 edges. However, Allen Schwenk and (independently) O. P. Lossers (Jack van Lint’s problem-solving seminar in Eindhoven) showed that you can’t partition the … Continue reading
Algebraic properties of chromatic polynomials, 2
My paper with Kerri Morgan on algebraic properties of chromatic roots (described here) has just appeared in the Electronic Journal of Combinatorics: you can find it here. I won’t say any more about it, except to pose a challenge which … Continue reading
Posted in open problems, Uncategorized
Tagged algebraic integer, chromatic polynomial, Galois group
2 Comments
Automorphism groups of transformation semigroups
I have been in the transformation semigroups game for nearly ten years now, but I still feel that I am finding my feet. Here is apparently a huge difference between permutation groups and transformation semigroups, one which is still not … Continue reading
Posted in doing mathematics, open problems, Uncategorized
Tagged automorphism, primitive groups, synchronization
Leave a comment
Problems
I have begun the long job of updating my collection of open problems. I would appreciate any help! My St Andrews problems are here, and are in pretty good shape (there are only 14 of them so this wasn’t a … Continue reading
Discrete mathematics in Derby
This week I have been at a conference on “Theoretical and Computational Discrete Mathematics” at the University of Derby, under the auspices of the Institute for Mathematics and its Applications. The University of Derby was founded as the Derby Diocesan … Continue reading
The power graph yet again
Five years ago, I posted a short update on the power graph of a group. Now, finally, the paper resulting from this has appeared on the arXiv; my coauthors are Ghodratollah Aalipour, Saieed Akbari, Reza Nikandish and Farzad Shaveisi. I … Continue reading
Circular repeated-measurements designs
My first paper in a real statistical journal has just been almost accepted (just a bit of re-formatting …) The paper is entitled “On optimality and construction of circular repeated-measurements designs”, the other authors are R. A. Bailey, K. Filipiak, J. Kunert and A. Markiewicz. … Continue reading
