  The class of defeasible logics is only vaguely defined -- it is defined by a
few exemplars and the general idea of efficient reasoning with defeasible
rules. The recent definition of the defeasible logic $DL(\partial_{||})$
introduced new features to such logics, which have repercussions that we
explore. In particular, we define a class of logics that accommodates the new
logic while retaining the traditional properties of defeasible logics.
