arXiv research

The paper studies singularities on parallels of tangent developable surfaces of frontal curves.

Characterizes special curves on surface tangent bundles.

A directed curve is a possibly singular curve with well-defined tangent lines along the curve. Then the tangent surface to a directed curve is naturally defined as the ruled surface by tangent geodesics to the curve, whenever any affine connection is endowed with the ambient space. In this paper the local diffeomorphis…

Considering the tangent plane at a point to a surface in the four-dimensional Euclidean space, we find an invariant of a pair of two tangents in this plane. If this invariant is zero, the two tangents are said to be conjugate. When the two tangents coincide with a given tangent, then we obtain the normal curvature of t…

We give the complete solution to the local diffeomorphism classification problem of generic singularities which appear in tangent surfaces, in as wider situations as possible. We interpret tangent geodesics as tangent lines whenever a (semi-)Riemannian metric, or, more generally, an affine connection is given in an amb…

We give the complete solution to the local diffeomorphism classification problem of generic singularities which appear in tangent surfaces, in as wider situations as possible. We interpret tangent geodesics as tangent lines whenever a (semi-)Riemannian metric, or, more generally, an affine connection is given in an amb…

Study K-R flow on Hirzebruch surfaces, showing tangent flows are K-R flows with orbifold singularities.

Researchers calculate Hofer-Zehnder capacity for twisted tangent bundles over surfaces.

In this paper, we define the inverse surface of a tangent developable surface with respect to the sphere S_{c}(r) with the center $c\in \mathbb{E}^{3}$ and the radius r in 3-dimensional Euclidean space $\mathbb{E}^{3}$. We obtain the curvatures, the Christoffel symbols and the shape operator of this inverse surface by …

It is given the diffeomorphism classification on generic singularities of tangent varieties to curves with arbitrary codimension in a projective space. The generic classifications are performed in terms of certain geometric structures and differential systems on flag manifolds, via several techniques in differentiable …

Extends first-order flexes of surfaces to second-order flexes.

Geodesics on modular surface yield arithmetic 3-manifolds.

Geodesics of the same type on curved surfaces are randomly distributed.

Study shows unique tangent flow for Lagrangian surfaces with bounded mean curvature.

At any point of a surface in the four-dimensional Euclidean space we consider the geometric configuration consisting of two figures: the tangent indicatrix, which is a conic in the tangent plane, and the normal curvature ellipse. We show that the basic geometric classes of surfaces in the four-dimensional Euclidean spa…

In this study, we give the relationships between the conical curvatures of ruled surfaces drawn by the unit vectors of the ruling, central normal and central tangent of a regular ruled surface in the Euclidean -space. We obtain the differential equations characterizing slant ruled surfaces and if the reference ruled su…

In this paper, we develop the theory of singular hermitian metrics on vector bundles. As an application, we give a structure theorem of a projective manifold $X$ with pseudo-effective tangent bundle: $X$ admits a smooth fibration $X \to Y$ to a flat projective manifold $Y$ such that its general fiber is rationally conn…

Study shows how certain foliations in unit tangent bundles behave.

New surfaces show horocyclic flow isn't always minimal.

The paper explores how the Gauss curvature of Riemannian surfaces can be represented as the divergence of a vector field.

Unified study of surfaces using Clifford algebras.

Veering branched surfaces help construct geodesic flows on curved surfaces.

A mathematical paradox shows secant planes don't always form a tangent plane, but some analogies hold with a specific vector product.

The paper classifies degenerate almost complex surfaces in a nearly Kähler space.

Study defines hyper-dual spheres and ruled surfaces, proving geometric relationships.

This paper is a continuation of the previous paper of the author[M]. We show that an affine deformation space of a hyperbolic surface of type (g,b) can be parametrized by Margulis invariants and affine twist parameters with a certain decomposition of the surface, which are associated with the Fenchel-Nielsen coordinate…

We classify compact Kähler manifolds with semi-positive holomorphic bisectional and big tangent bundles. We also classify compact complex surfaces with semi-positive tangent bundles and compact complex $3$-folds of the form $P(T^*X)$ whose tangent bundles are nef. Moreover, we show that if $X$ is a Fano manifold such t…

In the tangent plane at any point of a surface in the four-dimensional Euclidean space we consider an invariant linear map of Weingarten-type and find a geometrically determined moving frame field. Writing derivative formulas of Frenet-type for this frame field, we obtain eight invariant functions. We prove a fundament…

Study shows generic surfaces avoid complex flow patterns.

Regularizes 3D inverse scattering with tangent-point energy for better solutions.

Study bi-Hermitian metrics on complex surfaces and solve geometric PDEs.

In [31,32,33] the Gauss-Bonnet formulas for coherent tangent bundles over compact oriented surfaces (without boundary) were proved. We establish the Gauss-Bonnet theorem for coherent tangent bundles over compact oriented surfaces with boundary. We apply this theorem to investigate global properties of maps between surf…

The paper derives Gauss-Bonnet formulas for mappings between surfaces with boundary.

Partial coverings of hyperbolic surfaces equidistribute with geodesics.

We study the totally null surfaces of the neutral Kaehler metric on certain 4-manifolds. The tangent spaces of totally null surfaces are either self-dual ($α$-planes) or anti-self-dual ($β$-planes) and so we consider $α$-surfaces and $β$-surfaces. The metric of the examples we study, which include the spaces of oriente…

The paper studies how surfaces move by mean curvature flow and what happens at singular points.

Study on curves around a Whitney umbrella focusing on geodesic and normal curvatures.

The paper derives new Gauss-Bonnet formulas for frontal bundles over surfaces with boundary.

The paper classifies helix curves on a pseudo-Riemannian surface.

This is a survey article on recognition problem of frontal singularities. We specify geometrically several frontal singularities and then we solve the recognition problem of such singularities, giving explicit normal forms. We combine the recognition results by K. Saji and several arguments on openings, which was perfo…

Study on homeomorphisms preserving $C^1$ curves on surfaces.

In this note, we combine the work of Ilmanen and of Colding-Ilmanen-Minicozzi to observe a uniqueness property for tangent flows at the first singular time of a smooth mean curvature flow of a closed surface in 3-dimensional Euclidean space. Specifically, if, at a fixed singular point, one tangent flow is a positive in…

It is well known that a k-dimensional smooth surface in a Euclidean space cannot be tangent to a non-involutive distribution of k-dimensional planes. In this paper we discuss the extension of this statement to weaker notions of surfaces, namely integral and normal currents. We find out that integral currents behave to …

The study examines singularities in flows with curvature bounds and identifies unique tangent flows.

The paper finds lower bounds for volumes of complex geometric structures.

We partially resolve a conjecture of Meeks on the asymptotic behavior of minimal surfaces in $\mathbb{R}^3$ with quadratic area growth.

An explanation is given for the initially surprising ubiquity of separating sets in normal complex surface germs. It is shown that they are quite common in higher dimensions too. The relationship between separating sets and the geometry of the metric tangent cone of Bernig and Lytchak is described. Moreover, separating…

In-plane drill rotations are impossible for smooth shells.