Results 101 to 110 of about 112,777 (272)

CR-hypersurfaces of the six-dimensional sphere

International Journal of Mathematics and Mathematical Sciences, 1994
We proved that there does not exist a proper CR-hypersurface of S6 with parallel second fundamental form. As a result of this we showed that S6 does not admit a proper CR-totally umbilical hypersurface.
M. A. Bashir
doaj   +1 more source

The birational geometry of GIT quotients

Bulletin of the London Mathematical Society, EarlyView.
Abstract Geometric invariant theory (GIT) produces quotients of algebraic varieties by reductive groups. If the variety is projective, this quotient depends on a choice of polarisation; by work of Dolgachev–Hu and Thaddeus, it is known that two quotients of the same variety using different polarisations are related by birational transformations.
Ruadhaí Dervan, Rémi Reboulet
wiley   +1 more source

Monodromy of a family of hypersurfaces [PDF]

Annales scientifiques de l'École normale supérieure, 2009
Let $Y$ be an $(m+1)$-dimensional irreducible smooth complex projective variety embedded in a projective space. Let $Z$ be a closed subscheme of $Y$, and $ $ be a positive integer such that $\mathcal I_{Z,Y}( )$ is generated by global sections. Fix an integer $d\geq +1$, and assume the general divisor $X \in |H^0(Y,\ic_{Z,Y}(d))|$ is smooth. Denote
V. Di Gennaro, FRANCO, DAVIDE
openaire   +5 more sources

What is the total Betti number of a random real hypersurface [PDF]

, 2011
We bound from above the expected total Betti number of a high degree random real hypersurface in a smooth real projective manifold. This upper bound is deduced from the equirepartition of critical points of a real Lefschetz pencil restricted to the ...
D. Gayet, Jean-Yves Welschinger
semanticscholar   +1 more source

Hilbert–Kunz multiplicity of powers of ideals in dimension two

Bulletin of the London Mathematical Society, EarlyView.
Abstract We study the behavior of the Hilbert–Kunz multiplicity of powers of an ideal in a local ring. In dimension 2, we provide answers to some problems raised by Smirnov, and give a criterion to answer one of his questions in terms of a “Ratliff–Rush version” of the Hilbert–Kunz multiplicity.
Alessandro De Stefani, Shreedevi K. Masuti, Maria Evelina Rossi, Jugal K. Verma   +3 more
wiley   +1 more source

Minimization of hypersurfaces

Mathematics of Computation
Let F ∈ Z [ x 0 , … , x n ] F \in \mathbb {Z}[x_0, \ldots , x_n] be homogeneous of degree  d d and assume that F F is not a ‘nullform’, i.e., there is an invariant 
Elsenhans, Andreas-Stephan, Stoll, Michael   +1 more
openaire   +2 more sources

Construction of the field of Norden — Timofeev planes of hypersurfacese quipped with distributions

Дифференциальная геометрия многообразий фигур, 2018
In the projective space the research of a hypersurface with three stron­gest mutual subbundles continues. The field of the invariant Norden — Ti­mofeev planes is constructed that is internally attached to the hypersurface.
N. Eliseeva
doaj  

Hypersurfaces in a Euclidean space with a Killing vector field

AIMS Mathematics
An odd-dimensional sphere admits a killing vector field, induced by the transform of the unit normal by the complex structure of the ambiant Euclidean space.
Mohammed Guediri, Sharief Deshmukh
doaj   +1 more source

On the equivalence of two curvature conditions for Lorentzian hypersurfaces

Arab Journal of Mathematical Sciences, 2017
Let n≥3. We show that semi-symmetry and Ricci-semisymmetry conditions are equivalent for any n-dimensional Lorentzian hypersurface in a Lorentzian space form with nonzero curvature.
Mohammed Guediri, Norah Alshehri
doaj   +1 more source

An Index Theorem for Modules on a Hypersurface Singularity [PDF]

, 2011
A topological interpretation of Hochster's Theta pairing of two modules on a hypersurface ring is given in terms of linking numbers. This generalizes results of M. Hochster and proves a conjecture of J. Steenbrink.
R. Buchweitz, D. Straten
semanticscholar   +1 more source