On endomorphisms of the bicyclic semigroup and the extended bicyclic semigroup

Oleg Gutik, Oksana Prokhorenkova, Diana Sekh

It is proved that the semigroups $\mathbf{End}({\mathbf{B}}_{\omega })$ and $\mathbf{End}({\mathbf{B}}_{\mathbb{Z}})$ of the endomorphisms of the bicyclic semigroup $…