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Given a trivalent graph in the 3-dimensional Euclidean space, we call it a discrete surface because it has a tangent space at each vertex determined by its neighbor vertices. To abstract a continuum object hidden in the discrete surface, we…

Differential Geometry · Mathematics 2022-03-31 Motoko Kotani , Hisashi Naito , Chen Tao

The main aim of this paper is to investigate Darboux rectifying curves on a smooth surface immersed in the Euclidean space. First, we discuss the component of the position vector of a Darboux rectifying curve on a smooth immersed surface…

Differential Geometry · Mathematics 2021-04-06 Buddhadev Pal , Akhilesh Yadav

We introduce two basic invariant forms which define generic surface in 3-space uniquely up to Lie sphere equivalence. Two particularly interesting classes of surfaces associated with these invariants are considered, namely, the Lie-minimal…

dg-ga · Mathematics 2007-05-23 E. V. Ferapontov

A notion of dual curve for pseudoholomorphic curves in 4--manifolds turns out to be possible only if the notion of almost complex structure structure is slightly generalized. The resulting structure is as easy (perhaps easier) to work with,…

Differential Geometry · Mathematics 2007-05-23 Benjamin McKay

Willmore surfaces are the extremals of the Willmore functional (possibly under a constraint on the conformal structure). With the characterization of Willmore surfaces by the (possibly perturbed) harmonicity of the mean curvature sphere…

Differential Geometry · Mathematics 2019-04-01 A. C. Quintino

A discrete conformality for hyperbolic polyhedral surfaces is introduced in this paper. This discrete conformality is shown to be computable. It is proved that each hyperbolic polyhedral metric on a closed surface is discrete conformal to a…

Geometric Topology · Mathematics 2014-01-21 Xianfeng Gu , Ren Guo , Feng Luo , Jian Sun , Tianqi Wu

A conformal immersion of a 2-torus into the 4-sphere is characterized by an auxiliary Riemann surface, its spectral curve. This complex curve encodes the monodromies of a certain Dirac type operator on a quaternionic line bundle associated…

Differential Geometry · Mathematics 2012-12-21 Christoph Bohle , Franz Pedit , Ulrich Pinkall

The notion of a generalized harmonic inverse mean curvature surface in the Euclidean four-space is introduced. A backward B\"{a}cklund transform of a generalized harmonic inverse mean curvature surface is defined. A Darboux transform of a…

Differential Geometry · Mathematics 2013-04-11 Katsuhiro Moriya

We investigate the geometry of holomorphic curves and complex surfaces from the perspective of singularity theory. We show that, with a suitable choice of a complex bilinear symmetric form, the families of functions and mappings that…

Differential Geometry · Mathematics 2025-12-23 Amanda Dias Falqueto , Farid Tari

In Part I, we develop the notions of a Moebius structure and a conformal Cartan geometry, establish an equivalence between them; we use them in Part II to study submanifolds of conformal manifolds in arbitrary dimension and codimension. We…

Differential Geometry · Mathematics 2010-06-30 Francis E. Burstall , David M. J. Calderbank

We analyze a variational time discretization of geodesic calculus on finite- and certain classes of infinite-dimensional Riemannian manifolds. We investigate the fundamental properties of discrete geodesics, the associated discrete…

Numerical Analysis · Mathematics 2013-03-25 Martin Rumpf , Benedikt Wirth

We detail the theory of Discrete Riemann Surfaces. It takes place on a cellular decomposition of a surface, together with its Poincar\'e dual, equipped with a discrete conformal structure. A lot of theorems of the continuous theory follow…

Complex Variables · Mathematics 2008-02-13 Christian Mercat

This paper combines image metamorphosis with deep features. To this end, images are considered as maps into a high-dimensional feature space and a structure-sensitive, anisotropic flow regularization is incorporated in the metamorphosis…

Numerical Analysis · Mathematics 2020-07-03 Alexander Effland , Erich Kobler , Thomas Pock , Marko Rajković , Martin Rumpf

In this paper, we introduce a definition of discrete conformality for triangulated surfaces with flat cone metrics and describe an algorithm for solving the problem of prescribing curvature, that is to deform the metric discrete conformally…

Computational Geometry · Computer Science 2014-12-23 Jian Sun , Tianqi Wu , Xianfeng Gu , Feng Luo

We define a transformation on harmonic maps from a Riemann surface into the 2-sphere which depends on a complex parameter, the so-called mu-Darboux transformation. In the case when the harmonic map N is the Gauss map of a constant mean…

Differential Geometry · Mathematics 2014-07-24 F. E. Burstall , J. F. Dorfmeister , K. Leschke , A. Quintino

In this paper, we determine the topology of the spaces of convex polyhedra inscribed in the unit $2$-sphere and the spaces of strictly Delaunay geodesic triangulations of the unit $2$-sphere. These spaces can be regarded as discretized…

Geometric Topology · Mathematics 2023-05-31 Yanwen Luo , Tianqi Wu , Xiaoping Zhu

The purpose of this paper is to study transport equations on the unit tangent bundle of closed oriented Riemannian surfaces and to connect these to the transport twistor space of the surface (a complex surface naturally tailored to the…

Differential Geometry · Mathematics 2024-01-29 Jan Bohr , Thibault Lefeuvre , Gabriel P. Paternain

We consider a general theory of curvatures of discrete surfaces equipped with edgewise parallel Gauss images, and where mean and Gaussian curvatures of faces are derived from the faces' areas and mixed areas. Remarkably these notions are…

Differential Geometry · Mathematics 2017-09-06 Alexander I. Bobenko , Helmut Pottmann , Johannes Wallner

We develop a linear theory of discrete complex analysis on general quad-graphs, continuing and extending previous work of Duffin, Mercat, Kenyon, Chelkak and Smirnov on discrete complex analysis on rhombic quad-graphs. Our approach based on…

Complex Variables · Mathematics 2017-03-14 Alexander I. Bobenko , Felix Günther

We consider the class of compact Riemann surfaces which are ramified coverings of the Riemann sphere $\hat{\mathbb{C}}$. Based on a triangulation of this covering of the sphere $\mathbb{S}^2\cong \hat{\mathbb{C}}$ and its stereographic…

Complex Variables · Mathematics 2018-09-14 Alexander I. Bobenko , Ulrike Bücking