4 papers
Polyunsaturated Posets and Graphs and the Greene-Kleitman Theorem
Glenn G. Chappell
A partition of a finite poset into chains places a natural upper bound on the size of a union of k antichains. A chain partition is k-saturated if this bound is achieved. Greene an…
A Matroid Generalization of a Result on Row-Latin Rectangles
Glenn G. Chappell
Let A be an m \times n matrix in which the entries of each row are all distinct. Drisko showed that, if m \ge 2n-1, then A has a transversal: a set of n distinct entries with no tw…
Coloring Distance Graphs on the Integers
Glenn G. Chappell
Given a set D of positive integers, the associated distance graph on the integers is the graph with the integers as vertices and an edge between distinct vertices if their differen…
A Lower Bound for Partial List Colorings
Glenn G. Chappell
Let G be an n-vertex graph with list-chromatic number . Suppose each vertex of G is assigned a list of t colors. Albertson, Grossman, and Haas conjecture that at least $t n…