Abstract
Let G be a solvable group and p a prime. If B is a p-block of G, then there is a graph associated to B, called the Brauer graph of B, that captures information about the decomposition numbers of B. By the definition of a block, this graph is connected. In a previous paper [1], it was shown that if the defect group of B is abelian, or if G has odd order, then there is an absolute bound on the diameter of this connected graph. In this paper we show that in fact there is an absolute bound of 35 for the diameter of the Brauer graph of any p-block of any solvable group. Moreover, if p ≥ 11, we use a new large orbit theorem (which may be of independent interest) to show that the diameter is at most 15.
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Acknowledgement
The project was supported by a grant from the Simons Foundation (No. 499532). The authors are grateful to the referee for the valuable suggestions which improved the manuscript.
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Cossey, J., Yang, Y. A bound on the diameter of the Brauer graph of a block of a solvable group. Isr. J. Math. 250, 115–138 (2022). https://doi.org/10.1007/s11856-022-2333-3
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DOI: https://doi.org/10.1007/s11856-022-2333-3