On special Rees matrix semigroups over semigroups
  In this paper we focus on Rees $I\times \Lambda$ matrix semigroups without zero over a semigroup $S$ with $\Lambda\times I$ sandwich matrix $P$, where $I$ is a singleton, $\Lambda$ is the factor semigroup of $S$ modulo the kernel $\theta_S$ of the right regular representation of $S$, and $P$ is a choice function on the collection of all $\theta _S$-classes of $S$. We describe the kernel of the right regular representation of this type of Rees matrix semigroups, and prove embedding theorems on them. Motivated by one of embedding theorems, we show how right commutative right cancellative semigroups can be constructed. We define the concept of a right regular sequence of semigroups, and show that every congruence on an arbitrary semigroup defines such a sequence. 
Attila Nagy and Csaba T\'oth
math.GR