Results 21 to 30 of about 208,740 (273)

Integral closures in real algebraic geometry

open access: yesJournal of Algebraic Geometry, 2020
We study the algebraic and geometric properties of the integral closure of different rings of functions on a real algebraic variety: the regular functions and the continuous rational functions.
Fichou, Goulwen   +2 more
openaire   +5 more sources

The Non-Tightness of a Convex Relaxation to Rotation Recovery

open access: yesSensors, 2021
We study the Perspective-n-Point (PNP) problem, which is fundamental in 3D vision, for the recovery of camera translation and rotation. A common solution applies polynomial sum-of-squares (SOS) relaxation techniques via semidefinite programming. Our main
Yuval Alfassi   +2 more
doaj   +1 more source

Algebraic cycles and approximation theorems in real algebraic geometry [PDF]

open access: yesTransactions of the American Mathematical Society, 1993
Let \(M\) be a compact orientable smooth manifold of dimension \(\geq 5\). This paper shows which subgroups \(G \subset H_ 2 (M, {\mathbf Z}/2)\) can possibly be the subgroup of two dimensional algebraic cycles in an algebraic model of \(M\). It shows that the possible \(G\)'s are exactly those containing the Poincaré dual of the second Stieffel ...
Bochnak, J., Kucharz, W.
openaire   +1 more source

On singularities of real algebraic sets and applications to kinematics

open access: yesOpen Mathematics, 2020
We address the question of identifying non-smooth points in Vℝ(I){{\bf{V}}}_{{\mathbb{R}}}(I) the real part of an affine algebraic variety. Two simple algebraic criteria will be formulated and proven.
Diesse Marc
doaj   +1 more source

Real Representation of the Polarimetric Scattering Matrix for Monostatic Radar

open access: yesRemote Sensing, 2023
Synthetic aperture radar with polarimetric diversity is a powerful tool in remote sensing. Each pixel is described by the scattering matrix corresponding to the emission/reception polarization states (usually horizontal and vertical).
Madalina Ciuca   +4 more
doaj   +1 more source

Noncommutative real algebraic geometry of Kazhdan's property (T) [PDF]

open access: yes, 2015
It is well-known that a finitely generated group $\Gamma$ has Kazhdan's property (T) if and only if the Laplacian element $\Delta$ in ${\mathbb R}[\Gamma]$ has a spectral gap.
Ozawa, Narutaka
core   +3 more sources

The Hodge conjecture: The complications of understanding the shape of geometric spaces

open access: yesMètode Science Studies Journal: Annual Review, 2018
The Hodge conjecture is one of the seven millennium problems, and is framed within differential geometry and algebraic geometry. It was proposed by William Hodge in 1950 and is currently a stimulus for the development of several theories based on ...
Vicente Muñoz Velázquez
doaj   +1 more source

Pell’s equation, sum-of-squares and equilibrium measures on a compact set

open access: yesComptes Rendus. Mathématique, 2023
We first interpret Pell’s equation satisfied by Chebyshev polynomials for each degree $t$, as a certain Positivstellensatz, which then yields for each integer $t$, what we call a generalized Pell’s equation, satisfied by reciprocals of Christoffel ...
Lasserre, Jean B.
doaj   +1 more source

Detection of Daily Precipitation Structure in Shiraz Synoptic Station [PDF]

open access: yesنشریه جغرافیا و برنامه‌ریزی, 2020
Introduction Recently, issues raised by changes in precipitation, especially problems brought about by floods and droughts, along with the environmental effects of diminished rainfall, have underscored the importance of precipitation studies at different
mahdi narangifard   +3 more
doaj   +1 more source

A comparison of three heuristics to choose the variable ordering for CAD [PDF]

open access: yes, 2014
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 in another ...
Davenport, James H.   +4 more
core   +2 more sources

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