full transformations on X and of all injective partial transformations on X, respectively. Given
a non-empty subset Y of X, let, and. In 2008, Sanwong and Sommanee described the largest
regular subsemigroup and determined Green's relations of. In this paper, we present
analogous results for both and. For a finite set X with| X|≥ 3, the ranks of, and are well
known to be 4, 3 and 3, respectively. In this paper, we also compute the ranks of, and for any …