A harmonious colouring of a simple graph G is a proper vertex colouring such that each pair of colours appears together on at most one edge. The harmonious chromatic number h(G) is the least number of colours in such a colouring. It was shown by Hopcroft and Krishnamoorthy (1983) that the problem of determining the harmonious chromatic number of a graph is NP-hard. We show here that the problem...

A harmonious colouring of a simple graph G is a proper vertex colouring such that each pair of colours appears together on at most one edge. The harmonious chromatic number h(G) is the least number of colours in such a colouring. We obtain a new lower bound for the harmonious chromatic number of general graphs, in terms of the independence number of the graph, generalizing results of Moser [2].

The effect of harmonious versus non-harmonious color combinations in one aspect of information visualization effectiveness is considered. One focus is the relative suitability of two competing paradigms for determining color combinations that are harmonious. A second focus is the suitability of using opposing (i.e., opponent) colors for feature presentation in information visualization. The eff...

A common approach in the philosophy of love defines as caring about one another and promoting another's interests, aims values. The view faces several problems has been re-formulated to avoid them. However, here I argue that a larger re-formulation definition is needed order accommodate three instances what call 'non-harmonious' relationships. identify types non-harmonious (featuring problemati...