We study the existence of Milnor fibration on a big enough sphere at infinity for a mixed polynomial f: ℝ2n → ℝ2. By using strongly non-degenerate condition, we prove a counterpart of Némethi and Zaharia’s fibration theorem. In particular, we obtain a global version of Oka’s fibration theorem for strongly non-degenerate and convenient mixed polynomials.

Let $Y$ be an $(m+1)$-dimensional irreducible smooth complex projective variety embedded in a projective space. Let $Z$ be a closed subscheme of $Y$, and $\delta$ be a positive integer such that ${ℐ}_{Z,Y}\left(\delta \right)$ is generated by global sections. Fix an integer $d\ge \delta +1$, and assume the general divisor $X\in |H^0(Y,{ℐ}_{Z,Y}\left(d\right))|$ is smooth. Denote by $H^m{(X;\mathbb{Q})}_{\perp Z}^{\mathrm{van}}$ the quotient of $H^m(X;\mathbb{Q})$ by the cohomology of $Y$ and also by the cycle classes of the irreducible components of dimension $m$ of $Z$. In the present paper we prove that the monodromy representation on $H^m{(X;\mathbb{Q})}_{\perp Z}^{\mathrm{van}}$ for the family of smooth...

The paper is concerned with the relations between real and complex topological invariants of germs of real-analytic functions. We give a formula for the Euler characteristic of the real Milnor fibres of a real-analytic germ in terms of the Milnor numbers of appropriate functions.

Sia $f:{\mathbb{R}}^m\to {\mathbb{R}}^k$ con $m\ge k\ge 1$ una funzione analitica. Se il luogo critico di $f$ è compatto, esiste una fibrazione $C^{\mathrm{\infty }}$ localmente triviale associata ai livelli $f$. Supponiamo $k\ge 2$ e sia ${\pi }_k$ la proiezione $\left(x_1,\mathrm{\dots },x_{k-1},x_k\right)\mapsto \left(x_1,\mathrm{\dots },x_{k-1},x_k\right)$. Sotto una condizione sul luogo critico di $\tilde{f}={\pi }_k\circ f$ esiste anche una fibrazione $C^{\mathrm{\infty }}$ localmente triviale associata ai livelli di $\tilde{f}$. Siano $F$ e $\tilde{F}$ le fibre rispettitive, e $I$ l'intervallo unità reale. Dimostriamo qui che $\tilde{F}$ è omeomorfa al prodotto $F\times I$. Nel caso di polinomi studiamo criteri effettivi. Diamo inoltre un'applicazione del risultato...

We study pencils of plane curves $f_t=f-t{l}^N$, t ∈ ℂ, using the notion of polar invariant of the plane curve f = 0 with respect to a smooth curve l = 0. More precisely we compute the jacobian Newton polygon of the generic fiber $f_t$, t ∈ ℂ. The main result gives the description of pencils which have an irreducible fiber. Furthermore we prove some applications of the local properties of pencils to singularities at infinity of polynomials in two complex variables.

Soit $\phi :=(f,g):{ℂ}^2\to {ℂ}^2$ où $f$ et $g$ sont des applications polynomiales. Nous établissons le lien qui existe entre le polygone de Newton de la courbe réunion du discriminant et du lieu de non-propreté de $\phi$ et la topologie des entrelacs à l’infini des courbes affines $f^{-1}\left(0\right)$ et $g^{-1}\left(0\right)$. Nous en déduisons alors des conséquences liées à la conjecture du jacobien.

We give some criteria for the equisingularity of families of affine plane curves.

Let $𝒰$ be an open neighborhood of the origin in ${ℂ}^{n+1}$ and let $f:(𝒰,\mathbf{0})\to (ℂ,0)$ be complex analytic. Let $z_0$ be a generic linear form on ${ℂ}^{n+1}$. If the relative polar curve ${\Gamma }_{f,z_0}^1$ at the origin is irreducible and the intersection number $({\Gamma }_{f,z_0}^1{·V\left(f\right))}_{\mathbf{0}}$ is prime, then there are severe restrictions on the possible degree $n$ cohomology of the Milnor fiber at the origin. We also obtain some interesting, weaker, results when $({\Gamma }_{f,z_0}^1{·V\left(f\right))}_{\mathbf{0}}$ is not prime.

We define open book structures with singular bindings. Starting with an extension of Milnor’s results on local fibrations for germs with nonisolated singularity, we find classes of genuine real analytic mappings which yield such open book structures.

Soit $k$ un corps de caractéristique nulle et $f$ une fonction non constante définie sur une variété lisse. Nous définissons dans cet article unefibre de Milnor motivique à l’infiniqui appartient à un anneau de Grothendieck des variétés. Elle est définie en termes d’une compactification choisie, non nécessairement lisse, mais est indépendante de ce choix. Lorsque $k$ est le corps des nombres complexes, en utilisant le morphisme de réalisation de Hodge, elle se réalise en le spectre à l’infini de $f$. Nous...

For a holomorphic function on a complex manifold, we show that the vanishing cohomology of lower degree at a point is determined by that for the points near it, using the perversity of the vanishing cycle complex. We calculate this order of vanishing explicitly in the case the hypersurface has simple normal crossings outside the point. We also give some applications to the size of Jordan blocks for monodromy.