arXiv research

Two self-similar solutions found for time-like hypersurfaces in Minkowski spacetime.

We prove that every Kaehler metric, whose potential is a function of the time-like distance in the flat Kaehler-Lorentz space, is of quasi-constant holomorphic sectional curvatures, satisfying certain conditions. This gives a local classification of the Kaehler manifolds with the above mentioned metrics. New examples o…

There are considered 4-dimensional pseudo-Riemannian spaces with inner products of signature (3,1) and (2,2). The objects of investigation are space-like and time-like hyperspheres in the respective cases. These hypersurfaces are equipped with almost contact B-metric structures. The constructed manifolds are characteri…

A type of almost contact hypersurfaces with Norden metric of a Kaehler manifold with Norden metric is considered. The curvature tensor and the special sectional curvatures are characterized. The canonical connection on such manifolds is studied and the form of the corresponding Kaehler curvature tensor is obtained. Som…

In this paper we introduce the fourth fundamental form for the hypersurfaces in $H^{n+1}$ and the space-like hypersurfaces in $S_{1}^{n+1}$ and discuss the conformality of the normal Gauss maps of the hypersurfaces in $H^{n+1}$ and $S_{1}^{n+1}$. Particularly, we discuss the surfaces with conformal normal Gauss maps in…

Study of potential Carroll structures and special Carrollian manifolds for null hypersurfaces.

Study minimal time-like surfaces in 4D space-time, proving conditions for existence.

Improves Bernstein theorem for zero mean curvature hypersurfaces in Lorentz-Minkowski space.

In this paper, we prove that Euclidean hypersurfaces with almost extremal extrinsic radius or $λ_1$ have a spectrum that asymptotically contains the spectrum of the extremal sphere in the Reilly or Hasanis-Koutroufiotis Inequalities. We also consider almost extremal hypersurfaces which satisfy a supplementary bound on …

Defining Lorentzian Sabban frame of the unit speed time-like curves on de Sitter 2-space $\mathbb{S}^{2}_{1}$ and introducing space-like height function on the unit speed time-like curves on $\mathbb{S}^{2}_{1}$, the invariants of the unit speed time-like curves on $\mathbb{S}^{2}_{1}$ and geometric properties of de Si…

Canonical coordinates defined for minimal time-like surfaces in n-dimensional Minkowski space.

The paper studies extremal hypersurfaces in ellipsoids using centro-affine geometry.

We study time-like surfaces in the three-dimensional Minkowski space with diagonalizable second fundamental form. On any time-like W-surface we introduce locally natural principal parameters and prove that such a surface is determined uniquely (up to motion) by a special invariant function, which satisfies a natural no…

Study links Hopf differentials to curvature line flows on time-like CMC surfaces.

Study proves inequality for hypersurfaces and shows almost extremals are close to Wulff shape.

Study space-like and time-like surfaces in Robertson-Walker space-times with positive nullity.

Salkowski \cite{salkow}, one century ago, introduced a family of curves with constant curvature but non-constant torsion (Salkowski curves) and a family of curves with constant torsion but non-constant curvature (anti-Salkowski curves) in Euclidean 3-space $\e^3$. In this paper, we adapt definition of such curves to ti…

In this paper, position vectors of a time-like curve with respect to standard frame of Minkowski space E$^3_1$ are studied in terms of Frenet equations. First, we prove that position vector of every time-like space curve in Minkowski space E$^3_1$ satisfies a vector differential equation of fourth order. The general so…

The paper studies sections of time-like twistor spaces with specific covariant derivatives.

Study of generalized Bishop frames on time-like curves in 4D Lorentz space.

The study defines invariants for time-like surfaces with real asymptotic lines.

We prove that there does not exist global-in-time axisymmetric solutions to the time-like minimal submanifold system in Minkowski space. We further analyze the limiting geometry as the maximal time of existence is approached.

The paper classifies time-like surfaces in a static space-time.

New maximal surfaces solve Bernstein problems.

The paper examines the stability of two spherical self-similar solutions in Minkowski spacetime.

Study on surfaces in neutral space forms with zero mean curvature.

We study time-like hypersurfaces with vanishing mean curvature in the (3+1) dimensional Minkowski space, which are the hyperbolic counterparts to minimal embeddings of Riemannian manifolds. The catenoid is a stationary solution of the associated Cauchy problem. This solution is linearly unstable, and we show that this …

Study calculates spectra of minimal hypersurfaces in hyperbolic space.

Extremal Kähler submanifolds of complex projective spaces have natural extensions.

Paper proves a new criterion for time-like geodesics in flat spacetimes.

The paper studies umbilics on surfaces in Lorentz-Minkowski space.

Study of closed trajectories in hyperbolic plane with specific curvature constraints.

It is well-known that space-like maximal surfaces and time-like minimal surfaces in Lorentz-Minkowski 3-space R^3_1 have singularities in general. They are both characterized as zero mean curvature surfaces. We are interested in the case where the singular set consists of a light-like line, since this case has not been…

Study finds rigid submanifolds in spacelike waves under specific conditions.

Space-like maximal surfaces and time-like minimal surfaces in Lorentz-Minkowski3-space are both characterized as zero mean curvature surfaces. We are interested in the case where the zero mean curvature surface changes type from space-like to time-like at a given non-degenerate null curve. We consider this phenomenon a…

Unified estimates for mean curvature in Lorentz-Minkowski space.

We prove a theorem about an extremal property of Lobachevsky space among simply connected Riemannian manifolds of nonpositive curvature

The study constructs a Lorentzian length space and explores its properties and relationships with metric and causal geometry.

We study the conformally invariant variational problem for time-like curves in the $n$-dimensional Einstein universe defined by the conformal strain functional. We prove that the stationary curves are trapped into an Einsetin universe of dimension $2$, $3$ or $4$. We study the linearly-full stationary curves in a four-…

Lower bounds on periodic Finsler billiard trajectories in convex hypersurfaces.

We present in this paper the formalism for the splitting of a four-dimensional Lorentzian manifold by a set of time-like integral curves. Introducing the geometrical tensors characterizing the local spatial frames induced by the congruence (namely, the spatial metric tensor, the extrinsic curvature tensor and the Riema…

We prove that hypersurfaces of $\R^{n+1}$ which are almost extremal for the Reilly inequality on $λ_1$ and have $L^p$-bounded mean curvature ($p>n$) are Hausdorff close to a sphere, have almost constant mean curvature and have a spectrum which asymptotically contains the spectrum of the sphere. We prove the same result…

We consider the Laplacian in a domain squeezed between two parallel hypersurfaces in Euclidean spaces of any dimension, subject to Dirichlet boundary conditions on one of the hypersurfaces and Neumann boundary conditions on the other. We derive two-term asymptotics for eigenvalues in the limit when the distance between…

The parametrization theorem is derived in a flat nD pseudo-complex affine space. The pseudo-complex hyperbolic space accomodates n-number of uncompactified time-like extra dimensions with sugnature (s,r), where s and r are the numbers of minus and plus signs associated with the diagonalized metric matrix. The main resu…

Extending Lévi-Civita's concept to non-quadratic spaces, this study finds extremal compatible linear connections.

We relate in this note the classical Schwarzian derivative to the curvature of time-like curves in Lorentz surfaces of constant curvature.

Study Born-Infeld solitons and solve Björling problem for them.

The paper extends Ruh-Vilms theorem to hypersurfaces in Weitzenböck geometry.