On the ranks of the semigroup of A-decreasing finite transformations
Ping Zhao, Taijie You, Huabi Hu · Journal of Algebra and Its Applications · 2017
For [Formula: see text], let [Formula: see text] be the semigroup of all singular mappings on [Formula: see text]. For each nonempty subset [Formula: see text] of [Formula: see text], let [Formula: see text] be the semigroup of all [Formula: see text]-decreasing mappings on [Formula: see text]. In this paper we determine the rank and idempotent rank of the semigroup [Formula: see text].