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A first-order version of Pfaffian closure

Sergio Fratarcangeli (2008)

Fundamenta Mathematicae

The purpose of this paper is to extend a theorem of Speissegger [J. Reine Angew. Math. 508 (1999)], which states that the Pfaffian closure of an o-minimal expansion of the real field is o-minimal. Specifically, we display a collection of properties possessed by the real numbers that suffices for a version of the proof of this theorem to go through. The degree of flexibility revealed in this study permits the use of certain model-theoretic arguments for the first time, e.g. the compactness theorem....

A linear extension operator for Whitney fields on closed o-minimal sets

Wiesław Pawłucki (2008)

Annales de l’institut Fourier

A continuous linear extension operator, different from Whitney’s, for 𝒞 p -Whitney fields (p finite) on a closed o-minimal subset of n is constructed. The construction is based on special geometrical properties of o-minimal sets earlier studied by K. Kurdyka with the author.

A Note on a Theorem of Lion

Zofia Ambroży (2013)

Bulletin of the Polish Academy of Sciences. Mathematics

In this note we bind together Wilkie's complement theorem with Lion's theorem on geometric, regular and 0-regular families of functions.

Calculation of industrial robot trajectory in frame composite production

Mlýnek, Jaroslav, Martinec, Tomáš, Petrů, Michal (2017)

Programs and Algorithms of Numerical Mathematics

This article is focused on calculating the trajectory of an industrial robot in the production of composites for the automotive industry. The production technology is based on the winding of carbon fibres on a polyurethane frame. The frame is fastened to the end-effector of the robot arm (i.e. robot-end-effector, REE). The passage of the frame through the fibre processing head is determined by the REE trajectory. The position of the fibre processing head is fixed and is composed of three fibre guide...

Classification of obstructions for separation of semialgebraic sets in dimension 3.

F. Acquistapace, F. Broglia, C. Andradas (1997)

Revista Matemática de la Universidad Complutense de Madrid

Applying general results on separation of semialgebraic sets and spaces of orderings, we produce a catalogue of all possible geometric obstructions for separation of 3-dimensional semialgebraic sets and give some hints on how separation can be made decidable.

Compactification via le spectre réel d’espaces des classes de représentation dans SO ( n , 1 )

Taoufik Bouzoubaa (1994)

Annales de l'institut Fourier

Soit Γ un groupe de type fini non élémentaire. On note D n ( Γ ) l’ensemble des structures hyperboliques de dimension n sur Γ . D n ( Γ ) peut se réaliser comme fermé dans un espace semi-algébrique qui admet une compactification naturelle par le spectre réel. On note D n ( Γ ) sp le compactifié via le spectre _ réel de D n ( Γ ) . L’objet de cet article est de décrire les points ajoutés dans D n ( Γ ) sp . La compactification obtenue de cette manière permet d’interpréter “les points frontières” comme des représentations de Γ dans SO F + ( n , 1 ) F ( ) est un corps réel...

Computation of the distance to semi-algebraic sets

Christophe Ferrier (2010)

ESAIM: Control, Optimisation and Calculus of Variations

This paper is devoted to the computation of distance to set, called S, defined by polynomial equations. First we consider the case of quadratic systems. Then, application of results stated for quadratic systems to the quadratic equivalent of polynomial systems (see [5]), allows us to compute distance to semi-algebraic sets. Problem of computing distance can be viewed as non convex minimization problem: d ( u , S ) = inf x S x - u 2 , where u is in n . To have, at least, lower approximation of distance, we consider the dual...

Courbures intrinsèques dans les catégories analytico-géométriques

Andreas Bernig, Ludwig Bröcker (2003)

Annales de l’institut Fourier

Deux types de courbures sont associés à un sous-ensemble compact et définissable d'une variété riemannienne analytique réelle. Si la variété est de courbure constante, il y a des relations linéaires entre ces mesures. Comme application, nous démontrons une formule cinématique, définissons des densités locales, et nous étudions les volumes des simplexes réguliers.

Density of Morse functions on sets definable in o-minimal structures

Ta Lê Loi (2006)

Annales Polonici Mathematici

We present a tameness property of sets definable in o-minimal structures by showing that Morse functions on a definable closed set form a dense and open subset in the space of definable C p functions endowed with the Whitney topology.

Directional properties of sets definable in o-minimal structures

Satoshi Koike, Ta Lê Loi, Laurentiu Paunescu, Masahiro Shiota (2013)

Annales de l’institut Fourier

In a previous paper by Koike and Paunescu, it was introduced the notion of direction set for a subset of a Euclidean space, and it was shown that the dimension of the common direction set of two subanalytic subsets, called the directional dimension, is preserved by a bi-Lipschitz homeomorphism, provided that their images are also subanalytic. In this paper we give a generalisation of the above result to sets definable in an o-minimal structure on an arbitrary real closed field. More precisely, we...

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