Path Covering Spaces of Posets

Source abstract

In this paper we extend results concerning a kind of covering space for finite posets that bears some analogy to the topological theory of covering spaces. Previous work focused on ranked, locally-finite posets with a unique minimal element. In this previous work the notion of a covering space based on preservation of path weights was defined, and it was shown that, given a poset, there is a unique universal covering space which has an explicit description. Numerous examples of combinatorially significant posets and their universal covers were explored. In this paper we consider finite posets that have a unique minimal element, but that need not be ranked. We give a combinatorial description of these covering spaces, which we call path covers. We then show these covers naturally form a supersolvable lattice and deduce some of its properties. Finally, we investigate an analogue of deck transformations and give some results relating these transformations, poset automorphisms, and the automorphisms of the lattice of path covers.