New paper by Evgeny Khukhro (Univ. of Lincoln) and Pavel Shumyatsky (Univ. of Brasilia) “Profinite groups with an automorphism of prime order whose fixed points have finite Engel sinks” has been accepted for publication in the Monatshefte für Mathematik. The work was supported by FAPDF and CNPq-Brazil, and stems from the collaboration with University of Brasilia.
Abstract: A right Engel sink of an element of a group
is a set
such that for every
all sufficiently long commutators
belong to
. (Thus,
is a right Engel element precisely when we can choose
.) We prove that if a profinite group
admits a coprime automorphism
of prime order such that every fixed point of
has a finite right Engel sink, then
has an open locally nilpotent subgroup.
A left Engel sink of an element of a group
is a set
such that for every
all sufficiently long commutators
belong to
. (Thus,
is a left Engel element precisely when we can choose
.) We prove that if a profinite group
admits a coprime automorphism
of prime order such that every fixed point of
has a finite left Engel sink, then
has an open pronilpotent-by-nilpotent subgroup.