Operators and products in the lattice of existence varieties of regular semigroups.
Operators , and in the classes of -semigroups and -semirings.
Optics in Croke-Kleiner Spaces
We explore the interior geometry of the CAT(0) spaces , constructed by Croke and Kleiner [Topology 39 (2000)]. In particular, we describe a diffraction effect experienced by the family of geodesic rays that emanate from a basepoint and pass through a certain singular point called a triple point, and we describe the shadow this family casts on the boundary. This diffraction effect is codified in the Transformation Rules stated in Section 3 of this paper. The Transformation Rules have various applications....
Orbit measures, random matrix theory and interlaced determinantal processes
A connection between representation of compact groups and some invariant ensembles of hermitian matrices is described. We focus on two types of invariant ensembles which extend the gaussian and the Laguerre Unitary ensembles. We study them using projections and convolutions of invariant probability measures on adjoint orbits of a compact Lie group. These measures are described by semiclassical approximation involving tensor and restriction multiplicities. We show that a large class of them are determinantal....
Orbite di gruppi di permutazioni infiniti
Orbites d'un groupe algébrique dans l'espace des idéaux rationnels d'une algèbre enveloppante
Orbits in the Leech lattice.
Orbits, Invariants, and Representations Associated to Involutions of Reductive Groups.
Orbits of the Weyl group and a theorem of DeConcini and Procesi
Order and domains of attraction of control sets in flag manifolds.
Order Reduced Reidemeister-Schreier Subgroup Presentations and Applications.
Order relations on symmetric semigroups of transformations and on their homomorphic images.
Order theoretic variants of the fundamental theorem of compact semigroups.
Orderable 3-manifold groups
We investigate the orderability properties of fundamental groups of 3-dimensional manifolds. Many 3-manifold groups support left-invariant orderings, including all compact -irreducible manifolds with positive first Betti number. For seven of the eight geometries (excluding hyperbolic) we are able to characterize which manifolds’ groups support a left-invariant or bi-invariant ordering. We also show that manifolds modelled on these geometries have virtually bi-orderable groups. The question of virtual orderability...
Ordered groupoids and étendues
Ordered semigroups containing minimal and maximal elements.
Ordered sets which support inverse semigroups : Three examples.
Ordering D-classes and computing Schein rank is hard.
Ordering the local subsemigroups of a semigroup.
Ordering the symmetric group: why using the Iwahori-Hecke algebra? (Ordonner le groupe symétrique: Pourquoi utiliser l'algèbre de Iwahori-Hecke?)