Category Archives: doing mathematics

how is it done?

I’d like to see this solved

Posted on 17/06/2022 by Peter Cameron

Here is a problem that I would really like to see solved. I have spent quite a bit of time on it myself, and have suggested it to a few other people, but it still resists all attacks, though it … Continue reading →

Posted in doing mathematics, open problems | 9 Comments

Graphs on groups, 13

Posted on 05/02/2022 by Peter Cameron

There are many results about the universality, or otherwise, of various graphs defined on groups: answers to questions of the form “for which graphs Γ is there a group G such that Γ is isomorphic to an induced subgraph of … Continue reading →

Posted in doing mathematics, exposition, mathematics | Tagged , , | 2 Comments

Graphs on groups, 12

Posted on 03/01/2022 by Peter Cameron

One thing I have learned from the project is that the most interesting question about graphs defined on groups is this: given two types of graph defined on a group G, what is the class of groups for which the … Continue reading →

Posted in doing mathematics, exposition | Tagged , , , , | 1 Comment

Graphs on groups, 11

Posted on 02/01/2022 by Peter Cameron

A brief interlude to describe another recent preprint, and as in the preceding post I will concentrate on one result in the paper. I don’t know why it happens, but in this project one of the most interesting graph parameters … Continue reading →

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Graphs on groups, 10

Posted on 01/01/2022 by Peter Cameron

The lesson of this post and the next in the series is that the most interesting questions (to me, anyway) are not about the girth of the deep commuting graph but instead about the classes of groups G defined by … Continue reading →

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Graphs on groups, 9

Posted on 08/11/2021 by Peter Cameron

We continue to make progress with the graphs on groups project, but this post attempts to step back and look at the whole thing. What use is all this? Once, after I talked at a departmental colloquium at the University … Continue reading →

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Clive Sinclair

Posted on 18/09/2021 by Peter Cameron

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 →

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Graphs on groups, 8

Posted on 16/08/2021 by Peter Cameron

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 , , | 3 Comments

A new constant?

Posted on 23/05/2021 by Peter Cameron

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 , , | 8 Comments

Graphs on groups, 2

Posted on 27/01/2021 by Peter Cameron

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 →

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