The total chromatic number χ T (G) is the least number of colours needed to colour the vertices and edges of a graph G, such that no incident or adjacent elements (vertices or edges) receive the same colour. It is known that the problem of determining the total chromatic number is NP-hard and it remains NP-hard even for cubic bipartite graphs. Snarks are simple connected bridgeless cubic graphs...

The domination game on a graph G (introduced by B. Brešar, S. Klavžar, D.F. Rall [1]) consists of two players, Dominator and Staller, who take turns choosing a vertex from G such that whenever a vertex is chosen by either player, at least one additional vertex is dominated. Dominator wishes to dominate the graph in as few steps as possible, and Staller wishes to delay this process as much as po...

A graph G is chordless if no cycle in G has a chord. In the present work we investigate the chromatic index and total chromatic number of chordless graphs. We describe a known decomposition result for chordless graphs and use it to establish that every chordless graph of maximum degree ∆ ≥ 3 has chromatic index ∆ and total chromatic number ∆+1. The proofs are algorithmic in the sense that we ac...

The notion of dominators is generalized to include multiple-vertex dominators in addition to traditional single-vertex dominators. A multiple-vertex dominator of a vertex is a group of vertices that collectively dominate the vertex. An algorithm for computing immediate multiple-vertex dom-inators is presented. The immediate dominator information is expressed in the form of a directed acyclic gr...