Publications
Sort:
Open Access Research Article Issue
On the small Schröder semigroup S S n
AIMS Mathematics 2026, 11(6): 17191-17207
Published: 15 June 2026
Abstract PDF (254.3 KB) Collect
Downloads:0

Let [ n ] be a finite n-chain { 1 , 2 , , n }, and let L S n be the large Schröder monoid, consisting of all isotone and order-decreasing partial transformations on [ n ]. Furthermore, let S S n = { α L S n : 1 Dom α } be the subsemigroup of L S n , consisting of all transformations in L S n , not containing 1 in their domains. For 1 p k n, let I ( n , k ) = { α S S n : | Im α | k } be the two-sided ideal of S S n , consisting of transformations of height at most k, and let R S S n ( p ) denote the Rees quotient of I ( n , k ). It is shown in this article that the object S S n is a left monoid but not a right monoid. Moreover, it is shown that for any p k and any S { S S n , I ( n , k ) , R S S n ( p ) }, S is right abundant for all values of n, but not left abundant for all n 2. In addition, the rank of the Rees quotient R S S n ( p ) is shown to be equal to the rank of the two-sided ideal I ( n , p ), which is equal to ( n 1 p 1 ) + r = p n 1 ( n 1 r ) ( r 1 p 1 ) . Finally, the rank of S S n is determined to be 3 n 4.

Total 1