Constructing Type I nonmetrisable manifolds with given ϒ-trees

Nyikos has defined a tree, denoted ϒ, associated with any given Type I nonmetrisable manifold. In this paper, given an arbitrary well-pruned ω1-tree, T, we construct a Type I manifold such that its ϒ-tree is T. We show that whenever a Type I manifold contains a copy of ω1, its ϒ-tree must contain an uncountable branch. We address the problem of whether or not an arbitrary tree admits a Type I manifold which is ω1-compact.