“…The total domination number of G, denoted by γ t (G), is the minimum cardinality of a TDS of G, while the total restrained domination number of G, denoted by γ tr (G), is the minimum cardinality of a TRDS of G. Total domination in graphs is very well studied in graph theory (see, for example, the recent papers [8,[10][11][12]19]). Recent papers on total restrained domination in graphs can be found, for example, in [2,5,6,9,13,[15][16][17]21].…”