2011/03/21 by Puder, Doron
#Combinatorics (math.CO) #FOS: Mathematics #Group Theory (math.GR)
paper · doi:10.48550/arxiv.1103.4061
Let Fk be the free group on k generators, and let H≤ J≤ \Fk be subgroups of finite rank. We present a new elementary algorithm to determine whether H is a free factor of J. In particular, this algorithm can determine whether a given element w∈ Fk is primitive, i.e. whether it belongs to some basis of Fk.