We present the notion of scattering monodromy for a two degree of freedom hyperbolic oscillator and apply this idea to determine the Picard-Lefschetz monodromy of the isolated singular point of a quadratic function of two complex variables.

We investigate the quadratic homogeneous holomorphic vector fields on ${\mathbf{C}}^n$ that are semicomplete, this is, those whose solutions are single-valued in their maximal definition domain. To a generic quadratic vector field we rationally associate some complex numbers that turn out to be integers in the semicomplete case, thus showing that the linear equivalence classes of semicomplete vector fields are contained in some sort of lattice in the space of linear equivalence classes of quadratic ones. We prove...

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 obtain a complete list of simple framed curve singularities in ℂ² and ℂ³ up to the framed equivalence. We also find all the adjacencies between simple framed curves.

For a germ (X,0) of normal complex space of dimension n + 1 with an isolated singularity at 0 and a germ f: (X,0) → (ℂ,0) of holomorphic function with df(x) ≤ 0 for x ≤ 0, the fibre-integrals     $s\mapsto {\int }_{f=s}\varrho {\omega }^{\text{'}}\bigwedge \overline{{\omega }^{\text{'}\text{'}}},\varrho \in C_c^{\infty }\left(X\right),{\omega }^{\text{'}},{\omega }^{\text{'}\text{'}}\in {\Omega }_X^n$, are $C^{\infty }$ on ℂ* and have an asymptotic expansion at 0. Even when f is singular, it may happen that all these fibre-integrals are $C^{\infty }$. We study such maps and build a family of examples where also fibre-integrals for ${\omega }^{\text{'}},{\omega }^{\text{'}\text{'}}\in {⍹}_X$, the Grothendieck sheaf, are $C^{\infty }$.

We study Levi-flat real analytic hypersurfaces with singularities. We prove that the Levi foliation on the regular part of the hypersurface can be holomorphically extended, in a suitable sense, to neighbourhoods of singular points.

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.

In this article we investigate the natural domain of definition of a holonomy map associated to a singular holomorphic foliation of the complex projective plane. We prove that germs of holonomy between algebraic curves can have large sets of singularities for the analytic continuation. In the Riccati context we provide examples with natural boundary and maximal sets of singularities. In the generic case we provide examples having at least a Cantor set of singularities and even a nonempty open set...

Soit un germe de fonction analytique $f:({\mathbf{R}}^{n+1},0)\to (\mathbf{R},0)$, $n\ge 1$ à singularité isolée en $0\in {\mathbf{R}}^{n+1}$. Nous nous proposons d’étudier le développement asymptotique des intégrales de formes $C_c^{\infty }$, de degré $n$, sur les fibres de $f$. Nous montrons que ces développements asymptotiques peuvent être décrits à partir de l’action de la monodromie sur le groupe $H^n$ de la fibre de Milnor complexe.

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...