In this paper, we give a brief survey on four problems of Ramsey-type. The first and second problems are concerned about a sequence of numbers. The third one appears in discrete geometry and the… Expand

An edge-magic total labeling on a graph G is a one-to-one map λ from \( V (G) \ cup E(G)\) onto the integers 1,2, …, v + e, with the property that, given any edge xy, $$\lambda (x) + λ (xy) + \lambda (y) = k for some constant k.Expand

Let G be a connected graph G. Let c be a k-coloring of V(G) which induces an ordered partition Π = {S1,S2, ...,Sk} of V(G), where Si is the set of vertices receiving color i. The color code cΠ(ν) of… Expand