The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
David Forsyth - One of the best experts on this subject based on the ideXlab platform.
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Recognizing Algebraic Surfaces from their outlines
International Journal of Computer Vision, 1996Co-Authors: David ForsythAbstract:The outline in a single picture of a generic Algebraic Surface of degree three or greater completely determines the projective geometry of the Surface. The result holds for a generic perspective view of a generic Algebraic Surface, where the camera calibration parameters and the focal point are unknown. Known camera calibration appears not to reduce the projective ambiguity. The result is constructive.
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ICCV - Recognizing Algebraic Surfaces from their outlines
1993 (4th) International Conference on Computer Vision, 1Co-Authors: David ForsythAbstract:The author shows that the projective invariants of an Algebraic Surface can be computed from the outline of that Surface in a perspective view using an uncalibrated camera, by showing that an outline completely determines the projective geometry of an Algebraic Surface. A single perspective view of a generic Algebraic Surface of degree three or greater uniquely determines the projective geometry of the Surface. The result holds for an unknown focal point, and an uncalibrated camera. The projective ambiguity is not improved by using a calibrated camera. >
Luis Fernando Mello - One of the best experts on this subject based on the ideXlab platform.
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Polynomial Vector Fields on Algebraic Surfaces of Revolution
Results in Mathematics, 2020Co-Authors: Fabio Scalco Dias, Luis Fernando MelloAbstract:In the first part of the article we study polynomial vector fields of arbitrary degree in $${\mathbb {R}}^3$$ R 3 having an Algebraic Surface of revolution invariant by their flows. In the second part, we restrict our attention to an important case where the Algebraic Surface of revolution is a cubic Surface. We characterize all the possible configurations of invariant meridians and parallels that the vector fields can exhibit. Additionally we shall consider when the invariant parallels can be limit cycles. The results obtained in the second part can be adapted to the general Surfaces studied in the first part.
Lev Birbrair - One of the best experts on this subject based on the ideXlab platform.
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Lipschitz regular complex Algebraic sets are smooth
Proceedings of the American Mathematical Society, 2016Co-Authors: Lev Birbrair, Alexandre Fernandes, Edson SampaioAbstract:A classical Theorem of Mumford implies that a topologically regular complex Algebraic Surface in C 3 with an isolated singular point is smooth. We prove that any Lipschitz regular complex Algebraic set is smooth. No restriction on the dimension and no restriction on the singularity to be isolated is needed.
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Lipschitz regular complex Algebraic sets are smooth
arXiv: Algebraic Geometry, 2014Co-Authors: Lev Birbrair, Alexandre Fernandes, Edson Sampaio, Lê D. TrangAbstract:The classical Theorem of Mumford states that a topologically regular complex Algebraic Surface in $\mathbb{C}^3$ with an isolated singular point is smooth. We proof that any Lipschitz regular complex Algebraic set is smooth. No restriction on the dimension is needed. No restriction of singularity to be isolated is needed.
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On normal embedding of complex Algebraic Surfaces
arXiv: Algebraic Geometry, 2008Co-Authors: Lev Birbrair, Alexandre Fernandes, Walter D. NeumannAbstract:We construct examples of complex Algebraic Surfaces not admitting normal embeddings (in the sense of semiAlgebraic or subanalytic sets) with image a complex Algebraic Surface.
Frédéric Mangolte - One of the best experts on this subject based on the ideXlab platform.
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The group of automorphisms of a real rational Surface is n-transitive
Bulletin of the London Mathematical Society The Bulletin of the London Mathematical Society, 2009Co-Authors: Johannes Huisman, Frédéric MangolteAbstract:Let X be a rational nonsingular compact connected real Algebraic Surface. Denote by Aut(X) the group of real Algebraic automorphisms of X. We show that the group Aut(X) acts n-transitively on X, for all natural integers n. As an application we give a new and simpler proof of the fact that two rational nonsingular compact connected real Algebraic Surfaces are isomorphic if and only if they are homeomorphic as topological Surfaces.
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Real Algebraic morphisms on 2-dimensional conic bundles
Advances in Geometry, 2006Co-Authors: Frédéric MangolteAbstract:Given two nonsingular real Algebraicvarieties V and W, we consider the problem of deciding whether a smooth map f: V -> W can beapproximated by regular maps in the space ofsmooth maps from V to W. Our main result is a complete solution to this problem in case W is the usual 2-dimensional sphere and V is a real Algebraic Surface of negative Kodaira dimension.
Fabio Scalco Dias - One of the best experts on this subject based on the ideXlab platform.
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Polynomial Vector Fields on Algebraic Surfaces of Revolution
Results in Mathematics, 2020Co-Authors: Fabio Scalco Dias, Luis Fernando MelloAbstract:In the first part of the article we study polynomial vector fields of arbitrary degree in $${\mathbb {R}}^3$$ R 3 having an Algebraic Surface of revolution invariant by their flows. In the second part, we restrict our attention to an important case where the Algebraic Surface of revolution is a cubic Surface. We characterize all the possible configurations of invariant meridians and parallels that the vector fields can exhibit. Additionally we shall consider when the invariant parallels can be limit cycles. The results obtained in the second part can be adapted to the general Surfaces studied in the first part.