T-group (mathematics)

rdf:langString T-group (mathematics)

rdf:langString In mathematics, in the field of group theory, a T-group is a group in which the property of normality is transitive, that is, every subnormal subgroup is normal. Here are some facts about T-groups: * Every simple group is a T-group. * Every quasisimple group is a T-group. * Every abelian group is a T-group. * Every Hamiltonian group is a T-group. * Every nilpotent T-group is either abelian or Hamiltonian, because in a nilpotent group, every subgroup is subnormal. * Every normal subgroup of a T-group is a T-group. * Every homomorphic image of a T-group is a T-group. * Every solvable T-group is metabelian. The solvable T-groups were characterized by as being exactly the solvable groups G with an abelian normal Hall subgroup H of odd order such that the quotient group G/H is a Dedekind group and H is acted upon by conjugation as a group of power automorphisms by G. A PT-group is a group in which permutability is transitive. A finite T-group is a PT-group.