2018/07/31 by Skresanov, Saveliy V.
#05E18 #20B40 #20E28 #Computational Complexity (cs.CC) #FOS: Computer and information sciences #FOS: Mathematics #Group Theory (math.GR)
paper · doi:10.48550/arxiv.1807.11773
Let G be a finite group and let H be a proper subgroup of G of minimal index. By applying an old result of Y. Berkovich, we provide a polynomial algorithm for computing |G : H| for a permutation group G. Moreover, we find H explicitly if G is given by a Cayley table. As a corollary, we get an algorithm for testing whether a finite permutation group acts on a tree or not.