6 papers
Howson property and finitely generated intersection problem for monogenic inverse semigroups
Jung Won Cho, Craig Miller, Nik Ruškuc
An algebraic structure is said to have the Howson property if the intersection of any two finitely generated subalgebras is finitely generated. We explore the Howson property in th…
Twisted products of monoids
James East, Robert D. Gray, P. A. Azeef Muhammed +1
A twisting of a monoid is a map satisfying the identity . Together with an additive commutative monoid ,…
Maximal subgroups of free projection- and idempotent-generated semigroups with applications to partition monoids
James East, Robert D. Gray, P. A. Azeef Muhammed +1
This paper investigates the maximal subgroups of a free projection-generated regular -semigroup over a projection algebra , and their relationship to the maximal subg…
Semigroup Congruences and Subsemigroups of the Direct Square
Callum Barber, Nik Ruškuc
We investigate semigroups which have the property that every subsemigroup of which contains the diagonal is necessarily a congruence on $S…
On the number of subdirect products involving semigroups of integers and natural numbers
Ashley Clayton, Katie Reilly, Nik Ruskuc
We extend a recent result that for the (additive) semigroup of positive integers , there are continuum many subdirect products of up to i…
Heights of one- and two-sided congruence lattices of semigroups
M. Brookes, J. East, C. Miller +2
The height of a poset is the supremum of the cardinalities of chains in . The exact formula for the height of the subgroup lattice of the symmetric group is…