On linearly ordered HH-closed topological semilattices

We give a criterium when a linearly ordered topological semilattice is $H$-closed. We also prove that any linearly ordered $H$-closed topological semilattice is absolutely $H$-closed and we show that every linearly ordered semilattice is a dense subsemilattice of an $H$-closed topological semilattice

Topological semigroups of matrix units

We prove that the semigroup of matrix units is stable. Compact, countably compact and pseudocompact topologies τ on the infinite semigroup of matrix units Bλ such that (Bλ,τ ) is a semitopological (inverse) semigroup are described. We prove the following properties of an infinite topological semigroup of matrix units. On the infinite semigroup of matrix units there exists no semigroup pseudocompact topology. Any continuous homomorphism from the infinite topological semigroup of matrix units into a compact topological semigroup is annihilating. The semigroup of matrix units is algebraically h-closed in the class of topological inverse semigroups. Some H-closed minimal semigroup topologies on the infinite semigroup of matrix units are considered

Semigroup Closures of Finite Rank Symmetric Inverse Semigroups

We introduce the notion of semigroup with a tight ideal series and investigate their closures in semitopological semigroups, particularly inverse semigroups with continuous inversion. As a corollary we show that the symmetric inverse semigroup of finite transformations $\mathscr{I}_\lambda^n$ of the rank $\leqslant n$ is algebraically closed in the class of (semi)topological inverse semigroups with continuous inversion. We also derive related results about the nonexistence of (partial) compactifications of classes of semigroups that we consider.Comment: With the participation of the new coauthor - Jimmie Lawson - the manuscript has been substantially revised and expanded. Accordingly, we have also changed the manuscript titl

opological monoids of almost monotone injective co-finite partial selfmaps of positive integers

In this paper we study the semigroup$mathscr{I}_{infty}^{,Rsh!!!earrow}(mathbb{N})$ of partialco-finite almost monotone bijective transformations of the set ofpositive integers $mathbb{N}$. We show that the semigroup$mathscr{I}_{infty}^{,Rsh!!!earrow}(mathbb{N})$ hasalgebraic properties similar to the bicyclic semigroup: it isbisimple and all of its non-trivial group homomorphisms are eitherisomorphisms or group homomorphisms. Also we prove that every Bairetopology $au$ on$mathscr{I}_{infty}^{,Rsh!!!earrow}(mathbb{N})$ such that$(mathscr{I}_{infty}^{,Rsh!!!earrow}(mathbb{N}),au)$ isa semitopological semigroup is discrete, describe the closure of$(mathscr{I}_{infty}^{,Rsh!!!earrow}(mathbb{N}),au)$ ina topological semigroup and construct non-discrete Hausdorffsemigroup topologies on$mathscr{I}_{infty}^{,Rsh!!!earrow}(mathbb{N})$