A differential poset is a partially ordered set with raising and lowering operators U and D which satisfy the commutation relation DU-UD = rI for some constant r. This notion may ...
For a finite poset P = (V, ≤), let Bs(P) consist of all triples (x, y, z) ∈ V 3 such that either x < y < z or z < y < x. Similarly, for every finite, simple, and...
Let H be a fixed graph on h vertices. We say that a graph G is induced H-free if it does not contain any induced copy of H. Let G be a graph on n vertices and suppose that at leas...