An algorithmic criterion for basicness in dimension 2.
Bornes pour la régularité de Castelnuovo-Mumford des schémas non lisses
Nous montrons dans cet article des bornes pour la régularité de Castelnuovo-Mumford d’un schéma admettant des singularités, en fonction des degrés des équations définissant le schéma, de sa dimension et de la dimension de son lieu singulier. Dans le cas où les singularités sont isolées, nous améliorons la borne fournie par Chardin et Ulrich et dans le cas général, nous établissons une borne doublement exponentielle en la dimension du lieu singulier.
Bounds on degrees of projective schemes.
Computing the dimension of a semi-algebraic set.
Computing versal deformations.
Effective Estimates for Unirationality.
Effective nonvanishing, effective global generation
We prove a multiple-points higher-jets nonvanishing theorem by the use of local Seshadri constants. Applications are given to effectivity problems such as constructing rational and birational maps into Grassmannians, and the global generation of vector bundles.
Effective Nullstellensatz for arbitrary ideals
Let be polynomials in variables without a common zero. Hilbert’s Nullstellensatz says that there are polynomials such that . The effective versions of this result bound the degrees of the in terms of the degrees of the . The aim of this paper is to generalize this to the case when the are replaced by arbitrary ideals. Applications to the Bézout theorem, to Łojasiewicz–type inequalities and to deformation theory are also discussed.
Effectiveness - non effectiveness in semialgebraic and PL geometry.
Heights of varieties in multiprojective spaces and arithmetic Nullstellensätze
We present bounds for the degree and the height of the polynomials arising in some problems in effective algebraic geometry including the implicitization of rational maps and the effective Nullstellensatz over a variety. Our treatment is based on arithmetic intersection theory in products of projective spaces and extends to the arithmetic setting constructions and results due to Jelonek. A key role is played by the notion of canonical mixed height of a multiprojective variety. We study this notion...
Ideal as an intersection of zero-dimensional ideals and the Noether exponent.
On some generalizations of Jacobi's residue formula
On the finiteness theorem for rational maps on a variety of general type.
Pencils of binary quartics
Polynomial bounds for the oscillation of solutions of Fuchsian systems
We study the problem of placing effective upper bounds for the number of zeroes of solutions of Fuchsian systems on the Riemann sphere. The principal result is an explicit (non-uniform) upper bound, polynomially growing on the frontier of the class of Fuchsian systems of a given dimension having singular points. As a function of , this bound turns out to be double exponential in the precise sense explained in the paper.As a corollary, we obtain a solution of the so-called restricted infinitesimal...
Polynomial-time computation of the degree of a dominant morphism in zero characteristic. II.
Residue currents and complexity problems
Residues and effective Nullstellensatz.
Résultats récents d'algèbre commutative effective
Une inégalité de Lojasiewicz effective