“…The survey [10] presents these results and similar ones for other classes of transformation monoids, in particular, for monoids of order-preserving transformations and for some of their extensions. More recently, for instance, the papers [1,2,5,[11][12][13][14][15]23,33,34] are dedicated to the computation of the ranks of certain (classes of transformation) semigroups or monoids. Now, let G = (V , E) be a simple graph (i.e.…”