Progress towards the total domination game 34-conjecture

In this paper, we continue the study of the total domination game in graphs introduced in Henning et al. (2015), where the players Dominator and Staller alternately select vertices of GG. Each vertex chosen must strictly increase the number of vertices totally dominated, where a vertex totally dominates another vertex if they are neighbors. This process eventually produces a total dominating set SS of GG in which every vertex is totally dominated by a vertex in SS. Dominator wishes to minimize the number of vertices chosen, while Staller wishes to maximize it. The game total domination number, γtg(G), of GG is the number of vertices chosen when Dominator starts the game and both players play optimally. Henning et al. (in press) posted the 34-Game Total Domination Conjecture that states that if GG is a graph on nn vertices in which every component contains at least three vertices, then γtg(G)≤34n. In this paper, we prove this conjecture over the class of graphs GG that satisfy both the condition that the degree sum of adjacent vertices in GG is at least 44 and the condition that no two vertices of degree 11 are at distance 44 apart in GG. In particular, we prove that by adopting a greedy strategy, Dominator can complete the total domination game played in a graph with minimum degree at least 22 in at most 3n/43n/4 moves.