No Arabic abstract
The aim of this fisrt part is to introduce, for a rather large class of hypersurface singularities with 1 dimensionnal locus, the analog of the Brieskorn lattice at the origin (the singular point of the singular locus). The main results are the finitness theorem for the corresponding (a,b)-module obtained via Kashiwaras constructibility theorem, and non torsion results for a plane curve singularity (not nessarily reduced) and for the suspension of such non torsion cases with an isolated singularity.
Let (X_R, 0) be a germ of real analytic subset in (R^N, 0) of pure dimension n+1 with an isolated singularity at 0. Let (f_R,0) : (X_R, 0) --> (R,0) a real analytic germ with an isolated singularity at 0, such that its complexification f_C vanishes on the singular set S of X_C. We also assume that X_R-[0] is orientable. To each $ A in H^{0}(X_{mathbb{R}} - lbrace 0 rbrace ,mathbb {C}) $ we associate a $n-$cycle $ Gamma(A) $ (explicitly described) in the complex Milnor fiber of $f_{mathbb{C}}$ at 0 such that the non trivial terms in the asymptotic expansions of the oscillating integrals $ int_{A} e^{itau f(x)} phi(x) $ when $ tau to pm infty $ can be read from the spectral decomposition of $Gamma(A) $ relative to the monodromy of $f_{mathbb{C}}$ at 0 .
Let F be a finite extension of Qp, O_F its ring of integers and E a finite extension of Fp. The natural action of the unit group O_F* on O_F extends in a continuous action on the Iwasawa algebra E[[O_F]]. In this work, we show that non zero ideals of E[[O_F]] which are stable under O_F* are open. As a consequence, we deduce the fidelity of the action of E[[U]], with U the subgroup of upper unipotent matrices in GL2(O_F) on an irreducible admissible smooth E-representation of GL2(F). ----- Soit F une extension finie de Qp, danneau des entiers O_F et E une extension finie de Fp. Laction naturelle du groupes des unites O_F* sur O_F se prolonge alors en une action continue sur lalg`ebre dIwasawa E[[O_F]]. Dans ce travail, on demontre que les ideaux non nuls de E[[O_F]] stables par O_F* sont ouverts. En particulier, on en deduit la fidelite de laction de lalg`ebre dIwasawa des matrices unipotentes superieures de GL2(O_F) sur une representation lisse irreductible admissible de GL2(F).
Let ${rm F}$ be a rank-2 semi-stable sheaf on the projective plane, with Chern classes $c_{1}=0,c_{2}=n$. The curve $beta_{rm F}$ of jumping lines of ${rm F}$, in the dual projective plane, has degree $n$. Let ${rm M}_{n}$ be the moduli space of equivalence classes of semi-stables sheaves of rank 2 and Chern classes $(0,n)$ on the projective plane and ${cal C}_{n}$ be the projective space of curves of degree $n$ in the dual projective plane. The Barth morphism $$beta: {rm M}_{n}longrightarrow{cal C}_{n}$$ associates the point $beta_{rm F}$ to the class of the sheaf ${rm F}$. We prove that this morphism is generically injective for $ngeq 4.$ The image of $beta$ is a closed subvariety of dimension $4n-3$ of ${cal C}_{n}$; as a consequence of our result, the degree of this image is given by the Donaldson number of index $4n-3$ of the projective plane.
For a projective variety $X$ defined over a non-Archimedean complete non-trivially valued field $k$, and a semipositive metrized line bundle $(L, phi)$ over it, we establish a metric extension result for sections of $L^{otimes n}$ from a sub-variety $Y$ to $X$. We form normed section algebras from $(L, phi)$ and study their Berkovich spectra. To compare the supremum algebra norm and the quotient algebra norm on the restricted section algebra $V(L_{X|Y})$, two different methods are used: one exploits the holomorphic convexity of the spectrum, following an argument of Grauert; another relies on finiteness properties of affinoid algebra norms.
Using the theory of totally real number fields we construct a new class of compact complex non-K{a}hler manifolds in every even complex dimension and study their analytic and geometric properties.