Some hereditarily just infinite subgroups of

This work examines the commutator structure of some closed subgroups of the wild group of automorphisms of a local field with perfect residue field, a group we call . In particular, we establish a new approach to evaluating commutators in and using this method investigate the normal subgroup structure of some classes of index subgroups of as introduced by Klopsch. We provide new proofs of Fesenkoʹs results that lead to a proof that the torsion free group is hereditarily just infinite, and by extending his work, we also demonstrate the existence of a new class of hereditarily just infinite subgroups of which have non-trivial torsion.