Retracts of monounary algebras corresponding to groupoids
Revêtements «spinoriels» du groupe symplectique et indices de Maslov
Revisiting the symmetries of the quantum Smorodinsky-Winternitz system in dimensions.
Riemann and Klein surfaces with nodes viewed as quotients.
If G is a group of automorphisms that acts properly discontinuously on a Riemann or Klein surface X, then there exists a unique structure of Riemann or Klein surface on X/G such that the projection π: X → X/G is a morphism. The analogous result is not true when we deal with surfaces with nodes. In this paper we give a new definition of a group that acts properly discontinuously on a surface with nodes in order to obtain a similar theorem.
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 closing almost conjugacy for G-shifts of finite type
A G-shift of finite type (G-SFT) is a shift of finite type which commutes with the continuous action of a finite group G. For irreducible G-SFTs we classify right closing almost conjugacy, answering a question of Bill Parry.
Right compositions of semigroups
Right congruences In totally 0-simple semigroups.
Right division in Moufang loops
If is a group, and the operation is defined by then by direct verification is a quasigroup which satisfies the identity . Conversely, if one starts with a quasigroup satisfying the latter identity the group can be constructed, so that in effect is determined by its right division operation. Here the analogous situation is examined for a Moufang loop. Subtleties arise which are not present in the group case since there is a choice of defining identities and the identities produced by...
Right k-dense languages.
Right PP monoids with central idempotents.
Right Prime Ideals and Maximal Right Ideals in Semigroups
Rigidity, internality and analysability
We prove a version of Hrushovski's Socle Lemma for rigid groups in an arbitrary simple theory.
Rigidity of graph products of groups.
Rigidity of skew-angled Coxeter groups.
Rings all of whose additive endomorphisms are left multiplications.
Rings of Fricke Characters and Automorphism Groups of Free Groups.
Rings on certain classes of torsion-free Abelian groups
Rings on completely decomposable torsion-free Abelian groups
Rings which are semilattices of archimedean semigroups.