Idempotent Ranks in Strictly Partial Transformation Semigroups
Xiuliang Yang · Journal of Mathematical Research and Exposition · 2000
Let SP_n be the strictly partial transformation semigroup on X_n. For 2≤r≤n-2, We shall show that the subsemigroup is idempotent-generated, with both the rank and idempotent rank are equal to (r+1)S (n,r +1).