Representations of semigroups of idempotents
Residual finiteness in completely regular semigroup varieties.
Residual finiteness in permutation varieties of semigroups.
Residual finiteness of a class of semigroups presented by a single relation.
Resolutions for free partially commutative monoids.
Retractions and S-endomorphisms.
Retracts and monomorphism monoids in semigroup varieties.
Retracts of free monoids are nowhere dense with respect to finite group topologies and p-adic topologies.
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.
Right compositions of semigroups
Right congruences In totally 0-simple semigroups.
Right k-dense languages.
Right PP monoids with central idempotents.
Right Prime Ideals and Maximal Right Ideals in Semigroups
Rings which are semilattices of archimedean semigroups.
Rings with a certain condition on subsemigroups.
Roots of doubly-infinite increasing sequences.
Roots of increasing sequences.
R-unipotent congruences on regular semigroups.
Safety- and liveness-properties in propositional temporal logic: characterizations and decidability