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Author Archives: Peter Cameron
COP26
If I could send a message to the world leaders who will soon assemble in Glasgow, it would be, in the words of a St Andrews honorary graduate: What’ll you do now, my blue-eyed son?What’ll you do now, my darling … Continue reading
Joachim Neubüser
Another sad loss, with the death of Joachim Neubüser this week. He was the driving force behind the creation of the computer algebra system GAP. Even though I worked with John Cannon, the creator of the rival system Magma, I … Continue reading
Clive Sinclair
Yesterday I read the news that Clive Sinclair has died. This brought back memories of my first encounter with personal computers nearly 40 years ago. At the time I had a demanding job and three small children, and I was … Continue reading
Posted in doing mathematics, history, open problems
Tagged Neil Calkin, sum-free sets, ZX Spectrum
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Graphs on groups, 8
The dark clouds seem to have lifted a bit. Perhaps now, that the last rush of conferences for a while is over, life can return to something like normality … For me the most significant event was the last in … Continue reading
Posted in doing mathematics, events, open problems
Tagged graphs and groups, matching number, power graph
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A small problem
In connection with the research discussion about graphs and groups, I began to wonder which finite groups have the property that any two elements of the same order are conjugate. I thought about this, and got a certain distance, and … Continue reading
Bad times
Apologies for this. If you don’t like reading personal news, especially bad news, don’t persist. I am writing it down in the hope of putting it behind me. Back in early April, Rosemary had a very bad fall on the … Continue reading
Posted in Uncategorized
13 Comments
A little problem
In connection with the power graphs of unitary groups, I came across the following little number-theoretic conundrum. Can anyone solve it? Let q be an odd power of 2 (bigger than 2). Show that (q2−q+1)/3 is not a prime power … Continue reading
A new constant?
This is an appeal for help. Has anyone come across the constant 2.648102…? Here is the background, which connects with my previous posts about graphs on groups. We are interested in the clique number of the power graph of the … Continue reading
Posted in doing mathematics, open problems
Tagged clique number, Euler's function, power graph
8 Comments
Graphs on groups, 7
Nothing much to report, just a few connections. My long paper has appeared on-line ahead of publication in the International Journal of Group Theory. You can get a copy here (click on PDF). Next week, on Wednesday 12 May at … Continue reading
Graphs on groups, 6
The Groups and Graphs seminar has been running well. I find that I feel close to many people in the seminar even though most likely we have not met face to face. So I feel concerned about the Covid wave … Continue reading
