5 papers · 1 filter
On four-dimensional three-webs with integrable transversal distributions
Maks A. Akivis, Vladislav V. Goldberg
For a four-dimensional (nonisoclinicly geodesic) three-web W (3, 2, 2), a transversal distribution is defined by the torsion tensor of the web. In general, this distribution is…
On the Griffiths-Harris conjecture on varieties with degenerate Gauss mappings
M. A. Akivis, V. V. Goldberg, J. M. Landsberg
We exhibit examples of projective varieties with degenerate Gauss mappings and determine numerical invariants of such varieties. Our examples provide counter-examples to an asserte…
Lightlike hypersurfaces on a four-dimensional manifold endowed with a pseudoconformal structure of signature (2, 2)
Maks A. Akivis, Vladislav V. Goldberg
The authors study the geometry of lightlike hypersurfaces on a four-dimensional manifold endowed with a pseudoconformal structure . They prove that a lightl…
On some methods of construction of invariant normalizations of lightlike hypersurfaces
Maks A. Akivis, Vladislav V. Goldberg
The authors study the geometry of lightlike hypersurfaces on pseudo-Riemannian manifolds of Lorentzian signature. Such hypersurfaces are of interest in general relativity…
Lightlike hypersurfaces on manifolds endowed with a conformal structure of Lorentzian signature
Maks A. Akivis, Vladislav V. Goldberg
The authors study the geometry of lightlike hypersurfaces on manifolds endowed with a pseudoconformal structure of Lorentzian signature. Such hypersurf…