33 citations
12 papers
On flat complete causal Lorentzian manifolds
V. M. Gichev, O. S. Morozov
We describe up to finite coverings causal flat affine complete Lorentzian manifolds such that the past and the future of any point are closed near this point. We say that these man…
Surfaces in three-dimensional Lie groups
Dmitry A. Berdinsky, Iskander A. Taimanov
We derive the Weierstrass (or spinor) representation for surfaces in three-dimensional Lie groups Nil, \tilde{SL}_2, and Sol with Thurston's geometries and establish the generating…
Sublattices of lattices of convex subsets of vector spaces
Friedrich Wehrung, Marina V. Semenova
For a left vector space V over a totally ordered division ring F, let Co(V) denote the lattice of convex subsets of V. We prove that every lattice L can be embedded into Co(V) for…
Identities of conformal algebras and pseudoalgebras
Pavel Kolesnikov
For a given conformal algebra , we write down the correspondence between identities of the coefficient algebra $\Coeff C$ and identities of itself as of pseudoalgebra. In pa…
Extending representations of braid groups to the automorphism groups of free groups
Valerij G. Bardakov
We construct a linear representation of the group IA(F_n) of IA-automorphisms of a free group F_n, an extension of the Gassner representation of the pure braid group P_n. Although…
The virtual and universal braids
Valerij G. Bardakov
We study the structure of the virtual braid group. It is shown that the virtual braid group is a semi--direct product of the virtual pure braid group and the symmetric group. Also,…