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The Intrinsic Surface Finite Element Method (ISFEM) was recently proposed to solve Partial Differential Equations (PDEs) on surfaces. ISFEM proceeds by writing the PDE with respect to a local coordinate system anchored to the surface and…

Numerical Analysis · Mathematics 2024-10-08 Elena Bachini , Mario Putti

We present a novel convolutional neural network architecture for photometric stereo (Woodham, 1980), a problem of recovering 3D object surface normals from multiple images observed under varying illuminations. Despite its long history in…

Computer Vision and Pattern Recognition · Computer Science 2018-05-30 Tatsunori Taniai , Takanori Maehara

Minimal surfaces and Einstein manifolds are among the most natural structures in differential geometry. Whilst minimal surfaces are well understood, Einstein manifolds remain far less so. This exposition synthesises together a set of…

Differential Geometry · Mathematics 2025-08-19 Mia Beard

The ruled surface is a typical modeling surface in computer aided geometric design. It is usually given in the standard parametric form. However, it can also be in the forms than the standard one. For these forms, it is necessary to…

Symbolic Computation · Computer Science 2014-10-28 Sonia Perez-Diaza , Liyong Shen

We show that a realization of a closed connected PL-manifold of dimension n-1 in n-dimensional Euclidean space (n>2) is the boundary of a convex polyhedron (finite or infinite) if and only if the interior of each (n-3)-face has a point,…

Computational Geometry · Computer Science 2007-05-23 Konstantin Rybnikov

We give a short, self-contained, and easily verifiable proof that determining the outerthickness of a general graph is NP-hard. This resolves a long-standing open problem on the computational complexity of outerthickness. Moreover, our…

Computational Complexity · Computer Science 2026-02-10 Pin-Hsian Lee , Te-Cheng Liu , Meng-Tsung Tsai

This paper concerns the global theory of properly embedded spacelike surfaces in three-dimensional Minkowski space in relation to their Gaussian curvature. We prove that every regular domain which is not a wedge is uniquely foliated by…

Differential Geometry · Mathematics 2019-09-13 Francesco Bonsante , Andrea Seppi , Peter Smillie

In this paper, we prove three related results; (1) Extension of our result in [10] to all generic hypersurfaces. More precisely, the normal sheaf of a generic rational map $c_0$ to a generic hypersurface $X_0$ of $\mathbf P^n, n\geq 4$ has…

Algebraic Geometry · Mathematics 2014-10-14 Bin Wang

We show that in any triangulated 3-manifold, every index n topologically minimal surface can be transformed to a surface which has local indices (as computed in each tetrahedron) that sum to at most n. This generalizes classical theorems of…

Geometric Topology · Mathematics 2012-10-18 David Bachman

We consider threefolds that admit a fibration by K3 surfaces over a nonsingular curve, equipped with a divisorial sheaf that defines a polarisation of degree two on the general fibre. Under certain assumptions on the threefold we show that…

Algebraic Geometry · Mathematics 2019-08-15 Alan Thompson

In this paper, we present a new approach of creating PTAS to the TSP problems by defining a bounded-curvature surface embedded spaces. Using this definition we prove: - A bounded-curvature surface embedded spaces TSP admits to a PTAS. -…

Computational Geometry · Computer Science 2023-11-30 David Zisselman

Suppose that $N$ is a smooth manifold with a smooth Riemannian metric $g_0$, and that $\Gamma$ is a smooth submanifold of $N$. This paper proves that for a generic (in the sense of Baire category) smooth metric $g$ conformal to $g_0$, if…

Differential Geometry · Mathematics 2019-12-04 Brian White

Simplicial surfaces describe the incidence relations between vertices, edges and faces of triangulated 2-dimensional manifolds in a purely combinatorial way. By considering only the incidences of edges and faces, simplicial surfaces are…

Combinatorics · Mathematics 2025-06-26 Meike Weiß , Alice C. Niemeyer

We show that a strongly irreducible and boundary-strongly irreducible surface can be isotoped to be almost normal in a triangulated 3-manifold.

Geometric Topology · Mathematics 2013-02-14 David Bachman , Ryan Derby-Talbot , Eric Sedgwick

Typical-case computation complexity is a research topic at the boundary of computer science, applied mathematics, and statistical physics. In the last twenty years the replica-symmetry-breaking mean field theory of spin glasses and the…

Disordered Systems and Neural Networks · Physics 2014-06-17 Jin-Hua Zhao , Hai-Jun Zhou

Surface extraction from implicit neural representations modelling a single class surface is a well-known task. However, there exist no surface extraction methods from an implicit representation of multiple classes that guarantee topological…

Machine Learning · Computer Science 2026-02-19 Jash Vira , Andrew Myers , Simon Ratcliffe

In classical surface theory there are but few known examples of surfaces admitting nontrivial isometric deformations and fewer still non-simply-connected ones. We consider the isometric deformability question for an immersion x: M \to R^3…

Differential Geometry · Mathematics 2008-11-14 Brian Smyth , Giuseppe Tinaglia

Absorbing layers are sometimes required to be impractically thick in order to offer an accurate approximation of an absorbing boundary condition for the Helmholtz equation in a heterogeneous medium. It is always possible to reduce an…

Numerical Analysis · Mathematics 2014-01-20 Rosalie Bélanger-Rioux , Laurent Demanet

We use a new method to give conditions for the existence of a local isometric immersion of a Riemannian $n$-manifold $M$ in $\mathbb{R}^{n+k}$, for a given $n$ and $k$. These equate to the (local) existence of a $k$-tuple of scalar fields…

Differential Geometry · Mathematics 2019-09-02 Dan Gregorian Fodor

This is a survey on the classification of smooth surfaces in P^4 and smooth 3-folds in P^5. We recall the corresponding results arising from adjunction theory and explain how to construct examples via syzygies. We discuss some examples in…

alg-geom · Mathematics 2008-02-03 Wolfram Decker , Sorin Popescu