In article <email@example.com>, Tony Orlow <firstname.lastname@example.org> wrote:
> G. Frege wrote: > > On Tue, 11 Mar 2008 00:31:24 -0700, Virgil <Virgil@com.com> wrote: > > > >> If Tony wants to attach such an appendix to his trees, fine, but no one > >> else needs one [...]. > >> > > Even worse. Such a structure (graph) is not a /tree/ any more (since a > > tree doe not have cycles _by definbition_). > > > > > > F. > > > > If a normal tree can have a parent for every node except the root, then > this kind of tree can allow no cycles except at the subroot.
Not even there unless one changes the definition of "tree".