Results 31 to 40 of about 141,401 (262)
Covering rational ruled surfaces
Mathematics of Computation, 2017 We present an algorithm that covers any given rational ruled surface with two rational parametrizations. In addition, we present an algorithm that transforms any rational surface parametrization into a new rational surface parametrization without affine base points and such that the degree of the corresponding maps is preserved.
Sendra Pons, Juan Rafael +2 more
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Optimal bound for the number of (−1)-curves on extremal rational surfaces
International Journal of Mathematics and Mathematical Sciences, 2002 We give an optimal bound for the number of (−1)-curves on an extremal rational surface X under the assumption that −KX is numerically effective and having self-intersection zero.
Mustapha Lahyane
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Study on Optimal Sampling Analysis of Soil Moisture at Field Scale for Remote Sensing Applications
Atmosphere, 2023 With the rapid development of soil moisture estimation techniques involving remote sensing technology, the sampling designs used in soil moisture research are very important. To estimate the rational sample number for measuring near-surface soil moisture
Chunmei Wang +5 more
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Tori and surfaces violating a local-to-global principle for rationality
Comptes Rendus. MathématiqueWe show that even within a class of varieties where the Brauer–Manin obstruction is the only obstruction to the local-to-global principle for the existence of rational points (Hasse principle), this obstruction, even in a stronger, base change invariant ...
Kunyavskiĭ, Boris
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Shape preserving rational bi-cubic function
Egyptian Informatics Journal, 2012 The study is dedicated to the development of shape preserving interpolation scheme for monotone and convex data. A rational bi-cubic function with parameters is used for interpolation.
Malik Zawwar Hussain +2 more
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Rational Parametrization of Surfaces
Journal of Symbolic Computation, 1998 A rational surface is an algebraic surface birationally isomorphic to \( {\mathbb P}^{2} \). The author investigates the computational problems of rational parametrization of algebraic surfaces and formulates several algorithms for the purpose. He describes preliminary techniques (quadratic surfaces, inversion of birational maps, parametrization of a ...
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Characterization of rational ruled surfaces
Journal of Symbolic Computation, 2014 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 determine and find the standard form.
Li-Yong Shen, Sonia Pérez-Díaz
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Journal of High Energy Physics, 2018 We constructed several families of elliptic K3 surfaces with Mordell-Weil groups of ranks from 1 to 4. We studied F-theory compactifications on these elliptic K3 surfaces times a K3 surface.
Yusuke Kimura
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Positivity and Monotonicity Preserving Biquartic Rational Interpolation Spline Surface
Journal of Applied Mathematics, 2014 A biquartic rational interpolation spline surface over rectangular domain is constructed in this paper, which includes the classical bicubic Coons surface as a special case.
Xinru Liu, Yuanpeng Zhu, Shengjun Liu
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Implicitization of Rational Parametric Surfaces
Journal of Symbolic Computation, 1996 Let \(S\subset \mathbb{C}^3\) be a surface parametrized by a map \(F_a(s,t)= (f_1(s,t),\;f_2(s,t),\;f_3(s,t))\), where \(f_i\) are polynomials in \(s\) and \(t\). The implicitization process would find an equation \(f(x,y,z)=0\) such that the zero locus of the equation, \(W=\{(x,y, z)\mid f(x,y,z) =0\}\), is the smallest subset \(W\subset \mathbb{C}^3\)
George J. Fix +2 more
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