We describe the singularity of all but finitely-many germs in a pencil generated by two germs of plane curve sharing no tangent.

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.

Using the notion of the maximal polar quotient we characterize the critical values at infinity of polynomials in two complex variables. As an application we give a necessary and sufficient condition for a family of affine plane curves to be equisingular at infinity.

Let $(X,0)$ be a reduced, equidimensional germ of an analytic singularity with reduced tangent cone $(C_{X,0},0)$. We prove that the absence of exceptional cones is a necessary and sufficient condition for the smooth part ${𝔛}^0$ of the specialization to the tangent cone $\varphi :𝔛\to ℂ$ to satisfy Whitney’s conditions along the parameter axis $Y$. This result is a first step in generalizing to higher dimensions Lê and Teissier’s result for hypersurfaces of ${ℂ}^3$ which establishes the Whitney equisingularity of $X$ and its tangent cone under...

We will extend the infinitesimal criteria for the equisingularity (i.e. topological triviality) of deformations $f$ of germs of mappings $f_0:k^s$, $0\to k^t$, $0$ to non-finitely determined germs (these occur generically outside the “nice dimensions” for Mather, even among topologically stable mappings). The failure of finite determinacy is described geometrically by the “versality discriminant”, which is the set of points where $f_0$ is not stable (i.e. viewed as an unfolding it is not versal). The criterion asserts that...

We study the topological K-equivalence of function-germs (ℝn, 0) → (ℝ, 0). We present some special classes of piece-wise linear functions and prove that they are normal forms for equivalence classes with respect to topological K-equivalence for definable functions-germs. For the case n = 2 we present polynomial models for analytic function-germs.

We build two embedded resolution procedures of a quasi-ordinary singularity of complex analytic hypersurface, by using toric morphisms which depend only on the characteristic monomials associated to a quasi-ordinary projection of the singularity. This result answers an open problem of Lipman in Equisingularity and simultaneous resolution of singularities, Resolution of Singularities, Progress in Mathematics No. 181, 2000, 485- 503. In the first procedure the singularity is...

We prove that the set of asymptotic critical values of a $C^1$ function definable in an o-minimal structure is finite, even if the structure is not polynomially bounded. As a consequence, the function is a locally trivial fibration over the complement of this set.

We propose a refinement of the notion of blow-Nash equivalence between Nash function germs, which has been introduced in [2] as an analog in the Nash setting of the blow-analytic equivalence defined by T.-C. Kuo [13]. The new definition is more natural and geometric. Moreover, this equivalence relation still does not admit moduli for a Nash family of isolated singularities. But though the zeta functions constructed in [2] are no longer invariants for this new relation, thanks to a Denef & Loeser...

$\mu$-constant families of holomorphic function germs with isolated singularities are considered from a global perspective. First, a monodromy group from all families which contain a fixed singularity is studied. It consists of automorphisms of the Milnor lattice which respect not only the intersection form, but also the Seifert form and the monodromy. We conjecture that it contains all such automorphisms, modulo $\pm id$. Second, marked singularities are defined and global moduli spaces for right equivalence...