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In this paper we provide, first, a general symbolic algorithm for computing the symmetries of a given rational surface, based on the classical differential invariants of surfaces, i.e. Gauss curvature and mean curvature. In practice, the…

Computational Geometry · Computer Science 2024-10-25 Juan Juan Gerardo Alcázar , Carlos Hermoso , Hüsnü Anıl Çoban , Uğur Gözütok

Let $X$ be a complete simplicial toric variety over a finite field with a split torus $T_X$. For any matrix $Q$, we are interested in the subgroup $Y_Q$ of $T_X$ parameterized by the columns of $Q$. We give an algorithm for obtaining a…

Algebraic Geometry · Mathematics 2021-03-23 Esma Baran , Mesut Şahin

We present a method for computing all the symmetries of a rational ruled surface defined by a rational parametrization which works directly in parametric rational form, i.e. without computing or making use of the implicit equation of the…

Algebraic Geometry · Mathematics 2018-06-27 Alcázar Arribas , Juan Gerardo , Emily Quintero

Neural implicit surface representations have recently emerged as popular alternative to explicit 3D object encodings, such as polygonal meshes, tabulated points, or voxels. While significant work has improved the geometric fidelity of these…

Graphics · Computer Science 2023-06-27 Yanran Guan , Andrei Chubarau , Ruby Rao , Derek Nowrouzezahrai

In this paper we consider a family of algorithms for approximate implicitization of rational parametric curves and surfaces. The main approximation tool in all of the approaches is the singular value decomposition, and they are therefore…

Numerical Analysis · Mathematics 2016-05-30 Oliver J. D. Barrowclough , Tor Dokken

Using the framework of pastures and foundations of matroids developed by Baker-Lorscheid, we give algorithms to: (i) compute the foundation of a matroid, and (ii) compute all morphisms between two pastures. Together, these provide an…

Combinatorics · Mathematics 2023-07-27 Tianyi Zhang , Justin Chen

Parameterized algebraic curves and surfaces are widely used in geometric modeling and their manipulation is an important task in the processing of geometric models. In particular, the determination of the intersection loci between points,…

Commutative Algebra · Mathematics 2021-08-02 Laurent Busé , Marc Chardin

This work explores fundamental modeling and algorithmic issues arising in the well-established MapReduce framework. First, we formally specify a computational model for MapReduce which captures the functional flavor of the paradigm by…

Data Structures and Algorithms · Computer Science 2013-06-13 Andrea Pietracaprina , Geppino Pucci , Matteo Riondato , Francesco Silvestri , Eli Upfal

Most genuine multi-sided surface representations depend on a 2D domain that enables a mapping between local parameters and global coordinates. The shape of this domain ranges from regular polygons to curved configurations, but the simple…

Computational Geometry · Computer Science 2023-05-15 Péter Salvi

Existing 3D surface representation approaches are unable to accurately classify pixels and their orientation lying on the boundary of an object. Thus resulting in coarse representations which usually require post-processing steps to extract…

Computer Vision and Pattern Recognition · Computer Science 2019-01-23 Mateusz Michalkiewicz , Jhony K. Pontes , Dominic Jack , Mahsa Baktashmotlagh , Anders Eriksson

In this paper we present an algorithm to compute the (real and complex) straight lines contained in a rational surface, defined by a rational parameterization. The algorithm relies on the well-known theorem of Differential Geometry that…

Algebraic Geometry · Mathematics 2018-02-02 Juan Gerardo Alcázar , Jorge Caravantes

We present various facts on the graded Betti table of a projectively embedded toric surface, expressed in terms of the combinatorics of its defining lattice polygon. These facts include explicit formulas for a number of entries, as well as…

Algebraic Geometry · Mathematics 2016-12-05 Wouter Castryck , Filip Cools , Jeroen Demeyer , Alexander Lemmens

A matrix formalism is proposed for computations based on Picard--Lefschetz theory in a 2D case. The formalism is essentially equivalent to the computation of the intersection indices necessary for the Picard--Lefschetz formula and enables…

Mathematical Physics · Physics 2025-12-22 A. V. Shanin , A. I. Korolkov , N. M. Artemov , R. C. Assier

In the present paper, an integrated paradigm for topology optimization on complex surfaces with arbitrary genus is proposed. The approach is constructed based on the two-dimensional (2D) Moving Morphable Component (MMC) framework, where a…

Optimization and Control · Mathematics 2022-02-03 Wendong Huo , Chang Liu , Zongliang Du , Xudong Jiang , Zhengyu Liu , Xu Guo

We present first a brief review of the existing literature on shape optimization, stressing the recent use of Hamiltonian systems in topology optimization. In the second section, we collect some preliminaries on the implicit parametrization…

Optimization and Control · Mathematics 2022-11-23 Cornel Marius Murea , Dan Tiba

An algorithm is presented for the computation of the topology of a non-reduced space curve defined as the intersection of two implicit algebraic surfaces. It computes a Piecewise Linear Structure (PLS) isotopic to the original space curve.…

Commutative Algebra · Mathematics 2008-12-18 Daouda Niang Diatta , Bernard Mourrain , Olivier Ruatta

We consider the problem of computing the topology and describing the geometry of a parametric curve in $\mathbb{R}^n$. We present an algorithm, PTOPO, that constructs an abstract graph that is isotopic to the curve in the embedding space.…

Symbolic Computation · Computer Science 2022-02-18 Christina Katsamaki , Fabrice Rouillier , Elias Tsigaridas

A translational surface is a tensor product surface constructed from two space curves by translating one along the other. These surfaces are common within geometric modeling and, since their description is parametric, it is desirable to…

Algebraic Geometry · Mathematics 2026-02-20 Matthew Weaver

Given a family of rational curves depending on a real parameter, defined by its parametric equations, we provide an algorithm to compute a finite partition of the parameter space (${\Bbb R}$, in general) so that the shape of the family…

Symbolic Computation · Computer Science 2009-11-13 Juan Gerardo Alcazar

It is well known that not every combinatorial configuration admits a geometric realization with points and lines. Moreover, some of them do not even admit realizations with pseudoline arrangements, i.e., they are not topological. In this…

Combinatorics · Mathematics 2014-10-10 Jürgen Bokowski , Jurij Kovič , Tomaž Pisanski , Arjana Žitnik