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On irreducible components of a Weierstrass-type variety

Romuald A. Janik (1997)

Annales Polonici Mathematici

We give a characterization of the irreducible components of a Weierstrass-type (W-type) analytic (resp. algebraic, Nash) variety in terms of the orbits of a Galois group associated in a natural way to this variety. Since every irreducible variety of pure dimension is (locally) a component of a W-type variety, this description may be applied to any such variety.

On the space of real algebraic morphisms

Riccardo Ghiloni (2003)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

In this Note, we announce several results concerning basic properties of the spaces of morphisms between real algebraic varieties. Our results show a surprising intrinsic rigidity of Real Algebraic Geometry and illustrate the great distance which, in some sense, exists between this geometry and Real Nash one. Let us give an example of this rigidity. An affine real algebraic variety X is rigid if, for each affine irreducible real algebraic variety Z , the set of all nonconstant regular morphisms from...

Propriétés (Q) et (C). Variété commutante

Jean-Yves Charbonnel (2004)

Bulletin de la Société Mathématique de France

Soient X une variété algébrique complexe, lisse, irréductible, E et F deux espaces vectoriels complexes de dimension finie et μ un morphisme de X dans l’espace Lin ( E , F ) des applications linéaires de E dans F . Pour x X , on note E ( x ) et x · E le noyau et l’image de μ ( x ) , μ ¯ x le morphisme de X dans Lin ( E ( x ) , F / ( x · E ) ) qui associe à y l’application linéaire v μ ( y ) ( v ) + x · E . Soit i μ la dimension minimale de E ( x ) . On dit que μ ala propriété ( 𝐑 ) en x si i μ ¯ x est inférieur à i μ . Soient F * le dual de F , S ( F ) l’algèbre symétrique de F , μ l’idéal de 𝒪 X S ( F ) engendré par...

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