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Cylindrical algebraic decomposition (CAD) is a key tool for problems in real algebraic geometry and beyond. When using CAD there is often a choice over the variable ordering to use, with some problems infeasible in one ordering but simple…

Symbolic Computation · Computer Science 2015-02-12 Zongyan Huang , Matthew England , David Wilson , James H. Davenport , Lawrence C. Paulson

Cylindrical algebraic decomposition (CAD) is an important tool for the investigation of semi-algebraic sets. Originally introduced by Collins in the 1970s for use in quantifier elimination it has since found numerous applications within…

Symbolic Computation · Computer Science 2013-02-27 Matthew England

A new projection operator based on cylindrical algebraic decomposition (CAD) is proposed. The new operator computes the intersection of projection factor sets produced by different CAD projection orders. In other words, it computes the gcd…

Symbolic Computation · Computer Science 2014-05-20 Jingjun Han , Liyun Dai , Bican Xia

In this paper we introduce the notion of an Open Non-uniform Cylindrical Algebraic Decomposition (NuCAD), and present an efficient model-based algorithm for constructing an Open NuCAD from an input formula. A NuCAD is a generalization of…

Symbolic Computation · Computer Science 2014-03-27 Christopher W. Brown

Cylindrical algebraic decomposition (CAD) is an important tool for the investigation of semi-algebraic sets, with applications within algebraic geometry and beyond. We recently reported on a new implementation of CAD in Maple which…

Symbolic Computation · Computer Science 2013-06-14 Matthew England

Delineation of curvilinear structures is an important problem in Computer Vision with multiple practical applications. With the advent of Deep Learning, many current approaches on automatic delineation have focused on finding more powerful…

Computer Vision and Pattern Recognition · Computer Science 2017-12-07 Agata Mosinska , Pablo Marquez-Neila , Mateusz Kozinski , Pascal Fua

Cylindrical Algebraic Decompositions (CADs) endowed with additional topological properties have found applications beyond their original logical setting, including algorithmic optimizations in CAD construction, robot motion planning, and…

Algebraic Geometry · Mathematics 2026-01-16 Lucas Michel

Geometric Deep Learning techniques have become a transformative force in the field of Computer-Aided Design (CAD), and have the potential to revolutionize how designers and engineers approach and enhance the design process. By harnessing…

Computational Geometry · Computer Science 2025-07-08 Negar Heidari , Alexandros Iosifidis

This note shows the equivalence of two projection operators which both can be used in cylindrical algebraic decomposition (CAD) . One is known as Brown's Projection (C. W. Brown (2001)); the other was proposed by Lu Yang in his earlier work…

Symbolic Computation · Computer Science 2014-12-17 Yong Yao , Jia Xu , Lu Yang

A Cylindrical Algebraic Decomposition (CAD) is a decomposition of R^n into a finite collection of semialgebraic cells. A CAD satisfies the "frontier condition" if, for every cell C, there is a collection of cells of the decomposition whose…

Algebraic Geometry · Mathematics 2023-07-18 Hollie Baker

Cylindrical algebraic decomposition(CAD) is a key tool in computational algebraic geometry, particularly for quantifier elimination over real-closed fields. When using CAD, there is often a choice for the ordering placed on the variables.…

Symbolic Computation · Computer Science 2014-07-15 Zongyan Huang , Matthew England , David Wilson , James H. Davenport , Lawrence C. Paulson , James Bridge

By recasting metrical geometry in a purely algebraic setting, both Euclidean and non-Euclidean geometries can be studied over a general field with an arbitrary quadratic form. Both an affine and a projective version of this new theory are…

Metric Geometry · Mathematics 2007-05-23 Norman J. Wildberger

The Cylindrical Algebraic Decomposition (CAD) algorithm is a comprehensive tool to perform quantifier elimination over real closed fields. CAD has doubly exponential running time, making it infeasible for practical purposes. We propose to…

Discrete Mathematics · Computer Science 2013-01-22 Hari Krishna Malladi , Ambedkar Dukkipati

In this paper, we propose an incremental algorithm for computing cylindrical algebraic decompositions. The algorithm consists of two parts: computing a complex cylindrical tree and refining this complex tree into a cylindrical tree in real…

Symbolic Computation · Computer Science 2012-10-23 Changbo Chen , Marc Moreno Maza

Cylindrical algebraic decomposition (CAD) plays an important role in the field of real algebraic geometry and many other areas. As is well-known, the choice of variable ordering while computing CAD has a great effect on the time and memory…

Symbolic Computation · Computer Science 2021-02-05 Haokun Li , Bican Xia , Huiying Zhang , Tao Zheng

In 1994 Lazard proposed an improved method for cylindrical algebraic decomposition (CAD). The method comprised a simplified projection operation together with a generalized cell lifting (that is, stack construction) technique. For the proof…

Algebraic Geometry · Mathematics 2017-07-27 Scott McCallum , Adam Parusinski , Laurentiu Paunescu

Solid modeling is a technique underlying CAD software as we see it today, and its theories and algorithms are among the most fundamental milestones in the historical development of CAD. Basically, it has answered the question of what…

Graphics · Computer Science 2023-03-01 Qiang Zou

We investigate the distribution of cells by dimension in cylindrical algebraic decompositions (CADs). We find that they follow a standard distribution which seems largely independent of the underlying problem or CAD algorithm used. Rather,…

Symbolic Computation · Computer Science 2015-02-13 David Wilson , Matthew England , Russell Bradford , James H. Davenport

The concept of open weak CAD is introduced. Every open CAD is an open weak CAD. On the contrary, an open weak CAD is not necessarily an open CAD. An algorithm for computing projection polynomials of open weak CADs is proposed. The key idea…

Symbolic Computation · Computer Science 2019-03-28 Jingjun Han , Liyun Dai , Hoon Hong , Bican Xia

We give a new proof of the Semistable Reduction Theorem for curves. The main idea is to present a curve $Y$ over a local field $K$ as a finite cover of the projective line $X=\PP^1_K$. By successive blowups (and after replacing $K$ by a…

Algebraic Geometry · Mathematics 2012-11-21 Kai Arzdorf , Stefan Wewers