Tag Archives: integer sequences

9,21,27,45,81,153,…

This is the sequence of degrees of primitive groups which don’t synchronize a map of rank 3, equivalently graphs with clique number and chromatic number 3 having primitive automorphism groups. You could argue that the sequence should start with 3, … Continue reading

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The ADE affair, 3

Clusters, and the associated cluster algebras and cluster categories, form a hot topic in mathematics at the moment. Clusters are connected with topics such as Poisson geometry, integrable systems, representation theory and total positivity as well as combinatorial enumeration. I … Continue reading

Posted in exposition, open problems | Tagged , , , , , | 1 Comment