TY  - JOUR
A1  - Dimitrova, Ilinka
A1  - Koppitz, Jörg
T1  - On the maximal regular subsemigroups of ideals of order-preserving or order-reversing transformations
JF  - Semigroup forum
N2  - We characterize the maximal regular subsemigroups of the ideals of the semigroup of all order-preserving transformations as well as of the semigroup of all order-preserving or order-reversing transformations on a finite ordered set.
KW  - Transformation semigroups
KW  - Regular semigroups
KW  - Order-preserving transformations
KW  - Order-reversing transformations
KW  - Maximal subsemigroups
Y1  - 2011
U6  - https://doi.org/10.1007/s00233-010-9272-8
SN  - 0037-1912
VL  - 82
IS  - 1
SP  - 172
EP  - 180
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Dimitrova, Ilinka
A1  - Koppitz, Jörg
T1  - On relative ranks of the semigroup of orientation-preserving transformations on infinite chain with restricted range
JF  - Communications in algebra
N2  - Let X be an infinite linearly ordered set and let Y be a nonempty subset of X. We calculate the relative rank of the semigroup OP(X,Y) of all orientation-preserving transformations on X with restricted range Y modulo the semigroup O(X,Y) of all order-preserving transformations on X with restricted range Y. For Y = X, we characterize the relative generating sets of minimal size.
KW  - Order-preserving transformations
KW  - orientation-preserving
KW  - transformations
KW  - relative rank
KW  - restricted range
KW  - transformation
KW  - semigroups on infinite chain
Y1  - 2022
U6  - https://doi.org/10.1080/00927872.2021.2000998
SN  - 0092-7872
SN  - 1532-4125
VL  - 50
IS  - 5
SP  - 2157
EP  - 2168
PB  - Taylor & Francis Group
CY  - Philadelphia
ER  -