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Nel presente lavoro si studiano le applicazioni polinomiali proprie $φ : R^{n} \to R^{q} .$ In particolare si prova: 1) se $φ : R^{n} \to R$ è un'applicazione polinomiale tale che $φ^{- 1} (y)$ è compatto per ogni $y \in R$ , allora $φ$ è propria; 2) se $φ : R^{n} \to R^{q}$ è polinomiale a fibra compatta e $φ (R^{n})$ è chiuso in $R^{q}$ allora $φ$ è propria; 3) l'insieme delle applicazioni polinomiali proprie di $R^{n}$ in $R^{q}$ è denso, nella topologia $C^{\infty}$ , nello spazio delle applicazioni $C^{\infty}$ di $R^{n}$ in $R^{q}$ .

Some remarks on plane curves over fields of finite characteristic

Rita Pardini (1986)

Compositio Mathematica

Some remarks on the study of good contractions.

M. Andreatta (1995)

Manuscripta mathematica

Special linear systems and syzygies

Alberto Alzati (2008)

Collectanea Mathematica

Stable affine models for algebraic group actions.

Reichstein, Zinovy, Vonessen, Nikolaus (2004)

Journal of Lie Theory

Stein open subsets with analytic complements in compact complex spaces

Jing Zhang (2015)

Annales Polonici Mathematici

Let Y be an open subset of a reduced compact complex space X such that X - Y is the support of an effective divisor D. If X is a surface and D is an effective Weil divisor, we give sufficient conditions so that Y is Stein. If X is of pure dimension d ≥ 1 and X - Y is the support of an effective Cartier divisor D, we show that Y is Stein if Y contains no compact curves, $H^{i} (Y,_{Y}) = 0$ for all i > 0, and for every point x₀ ∈ X-Y there is an n ∈ ℕ such that $Φ_{| n D |}^{- 1} (Φ_{| n D |} (x ₀)) \cap Y$ is empty or has dimension 0, where $Φ_{| n D |}$ is the map from...

Structure of birational automorphism groups, I: non-uniruled varieties.

Masaki Hanamura (1988)

Inventiones mathematicae

Studies on the Painlevé Equations. III. Second and Fourth Painlevé Equations PII and PIV.

Kazuo Okamoto (1986)

Mathematische Annalen

Subjective polynomial maps, and a remark on the jacobian problem.

Ken McKenna, Lou Van den Dries (1990)

Manuscripta mathematica

Subsheaves of the cotangent bundle

Paolo Cascini (2006)

Open Mathematics

For any smooth projective variety, we study a birational invariant, defined by Campana which depends on the Kodaira dimension of the subsheaves of the cotangent bundle of the variety and its exterior powers. We provide new bounds for a related invariant in any dimension and in particular we show that it is equal to the Kodaira dimension of the variety, in dimension up to 4, if this is not negative.

Sui gruppi di sostituzioni lineari con coefficienti appartenenti a corpi quadratici immaginari

Luigi Bianchi (1892)

Mathematische Annalen

Sur des variétés toriques non projectives

Laurent Bonavero (2000)

Bulletin de la Société Mathématique de France

Sur la construction de la tangente à la courbe $ρ = \frac{f (ω)}{ω + ϕ (ω)}, f (ω)$ et $ϕ (ω)$ désignant des fonctions rationnelles des lignes trigonométriques de l’angle $ω$ , de ses multiples ou de ses parties aliquotes

G. Fouret (1880)

Nouvelles annales de mathématiques : journal des candidats aux écoles polytechnique et normale

Sur la structure birationelle de Bu.

M. Demazure (1979)

Inventiones mathematicae

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