Regularity and transitivity of local-automorphism semigroups of locally finite forests
Relations Invariant under semigroup actions.
Remarks on isomorphisms of regressive transformation semigroups.
Representable epimorphisms of monoids
Representation of inverse semigroups by local automorphisms and multi-automorphisms of groups and rings.
Representations of group and semigroup actions
Representations of semigroups by linear transformations, Part I.
Representations of semigroups by linear transformations,Part II..
Representations of semigroups of idempotents
Riemann surfaces in Stein manifolds with the Density property
We show that any open Riemann surface can be properly immersed in any Stein manifold with the (Volume) Density property and of dimension at least 2. If the dimension is at least 3, we can actually choose this immersion to be an embedding. As an application, we show that Stein manifolds with the (Volume) Density property and of dimension at least 3, are characterized among all other complex manifolds by their semigroup of holomorphic endomorphisms.
Sandwich sets and partial order.
Schützenberger groups and Chebyshev polynomials.
Schützenberger groups of ...-classes in the semigroup of all binary relations on a set.
Schützenberger groups of some even degree polynomials in S(R).
Second centralizers of partial transformations
Second centralizers of partial transformations on a finite set are determined. In particular, it is shown that the second centralizer of any partial transformation consists of partial transformations that are locally powers of .
Semi-automorphisms of transformation semigroups
Semigroups for which the continuum congruences form finite chains.
Semigroups in which ... and ... coincide for regular elements.
Semigroups in which each -class contains at most one regular ...-class.
Semigroups of ...-density continuous functions.