Top Posts
Recent comments
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
- Collecting reality
- 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
- Kourovka Notebook
- 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
- Ratio bound
- 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
Author Archives: Peter Cameron
EDI
We hear a lot about equality, diversity and inclusion now. Perhaps it would be good to remind ourselves of the formal definition. A and B are equal if, for all x, we have (x∈A) ↔ (x∈B). A and B are diverse if … Continue reading
Graphs on groups, 5
I gave two lectures on this stuff to a new research seminar on Groups and Graphs, run by Vijayakumar Ambat in Kochi, Kerala. The first was an introduction to the hierarchy, the second was about cographs and twin reduction, why … Continue reading
Posted in events, exposition, open problems
Tagged cograph, commuting graph, nilpotent group, perfect graph, power graph
2 Comments
Hoffman, Lovász and Haemers
At the weekend I attended remotely a memorial session for Alan Hoffman, organised by Bill Pulleyblank. I found it informative, as well as moving. Hoffman is well-known in the algebraic graph theory community for a number of remarkable achievements, including … Continue reading
Posted in events
Tagged Alan Hoffman, algebraic graph theory, eigenvalues, Laszlo Lovasz, optimization, WIllem Haemers
1 Comment
Three passages
[Dmitri] Egorov [founder of the Moscow School of Mathematics] was a very reserved and modest man, so much so that it would be easy to believe that he lived only for mathematics. […] His publications do not reveal any evidence … Continue reading
Posted in Uncategorized
5 Comments
Graphs on groups, 4
Here is a small problem, mixing group theory and number theory, which might appeal to someone. A couple of definitions. The power graph of a group G has an edge from x to y if one is a power of … Continue reading
Graphs on groups, 3
Since this stuff keeps growing, I have decided to keep the most recent version on the web. It is now nearly twice as long as the first version I circulated. If you are interested, please take a copy: it’s at … Continue reading
13th Iranian International Group Theory Conference
This week has been rather a rush. As well as the first week of semester (and my first ever experience of on-line undergraduate lecturing), I have been attending the 13th Iranian International Group Theory Conference in Urmia, Iran. (I had … Continue reading
Posted in events
Tagged Bernhard Neumann, Carlo Casolo, Eugenio Gianelli, Gareth Jones, Sasha Ivanov, Urmia
Leave a comment
Graphs on groups, 2
I wrote the long post about this to try to write it out of my system. No luck … I mentioned in that survey that every finite graph is embeddable as induced subgraph in the enhanced power graph, deep commuting … Continue reading
Posted in doing mathematics, mathematics
Tagged commuting graph, enhanced power graph
Leave a comment
Cheryl Praeger
Good news for a change. I just heard that Cheryl (my mathematical sister, third most prolific coauthor, and good friend) has been made a Companion of the Order of Australia. https://www.abc.net.au/news/2021-01-26/professor-cheryl-praeger-receives-companion-order-of-australia/13089958 Congratulations Cheryl!
