Fibrés de rang deux sur une courbe, fibré déterminant et fonctions thêta. II
Finiteness results for Abelian tree models
Equivariant tree models are statistical models used in the reconstruction of phylogenetic trees from genetic data. Here equivariant§ refers to a symmetry group imposed on the root distribution and on the transition matrices in the model. We prove that if that symmetry group is Abelian, then the Zariski closures of these models are defined by polynomial equations of bounded degree, independent of the tree. Moreover, we show that there exists a polynomial-time membership test for that Zariski closure....
Generic determinantal schemes and the smoothability of determinantal schemes of codimension 2.
Generic maps and modules
Generische determinantielle Singularitäten: Homologische Eigenschaften des Derivationenmoduls.
Gröbner bases and Stanley decompositions of determinantal rings.
Gröbner bases of certain determinantal ideals.
Hyperdéterminant d’un -homomorphisme
Etant donnés () des -modules non triviaux de dimensions respectives (avec ) et un -homomorphisme, nous montrons que l’hyperdéterminant de est nul sauf si les modules sont irréductibles et si l’homomorphisme est la multiplication des polynômes homogènes à deux variables.
Infinitesimal variations of hodge structure (III) : determinantal varieties and the infinitesimal invariant of normal functions
Miscellaneous results and conjuctures on the ring of commuting matrices.
Nouvelles surfaces à noeuds dans IP3.
On determinantal ideals which are set-theoretic complete intersections
On Hilbert polynomial of certain determinantal ideals.
Orbifold principal bundles on an elliptic fibration and parabolic principal bundles on a Riemann surface.
Let X be a compact Riemann surface and associated to each point p-i of a finite subset S of X is a positive integer m-i. Fix an elliptic curve C. To this data we associate a smooth elliptic surface Z fibered over X. The group C acts on Z with X as the quotient. It is shown that the space of all vector bundles over Z equipped with a lift of the action of C is in bijective correspondence with the space of all parabolic bundles over X with parabolic structure over S and the parabolic weights at any...
Polynomials homologically supported on degeneracy loci
Positive polynomials and hyperdeterminants
Let F be a homogeneous real polynomial of even degree in any number of variables. We consider the problem of giving explicit conditions on the coefficients so that F is positive definite or positive semi-definite. In this note we produce a necessary condition for positivity, and a sufficient condition for non-negativity, in terms of positivity or semi-positivity of a one-variable characteristic polynomial of F. Also, we revisit the known sufficient condition in terms of Hankel matrices.
Representation stability for syzygies of line bundles on Segre–Veronese varieties
The rational homology groups of packing complexes are important in algebraic geometry since they control the syzygies of line bundles on projective embeddings of products of projective spaces (Segre–Veronese varieties). These complexes are a common generalization of the multidimensional chessboard complexes and of the matching complexes of complete uniform hypergraphs, whose study has been a topic of interest in combinatorial topology. We prove that the multivariate version of representation stability,...
Resolutions of generic points lying on a smooth quadric.
Résultats sur la conjecture de dualité étrange sur le plan projectif
La conjecture de « dualité étrange » de Le Potier donne un isomorphisme entre l’espace des sections du fibré déterminant sur deux espaces de modules différents de faisceaux semi-stables sur le plan projectif . On considère deux classes orthogonales dans l’algèbre de Grothendieck telles que est de rang strictement positif et est de rang zéro, et on note et les espaces de modules de faisceaux semi-stables de classe , respectivement sur . Il existe sur (resp. ) un fibré déterminant...
Rings of Invariants and Linkage of Determinantal Ideals.