Roya Beheshti

  1. Spaces of rational curves in complete intersections.

    Authors: Roya Beheshti, N. Mohan Kumar
    Subjects: Algebraic Geometry
    Abstract

    We prove that the space of smooth rational curves of degree $e$ in a general
    complete intersection of multidegree $(d_1, ..., d_m)$ in $\PP^n$ is
    irreducible of the expected dimension if $\sum_{i=1}^m d_i <\frac{2n}{3}$ and
    $n$ is large enough. This generalizes the results of Harris, Roth and Starr
    \cite{hrs}, and is achieved by proving that the space of conics passing through
    any point of a general complete intersection has constant dimension if
    $\sum_{i=1}^m d_i$ is small compared to $n$.

  2. Fibers of Projections and Submodules of Deformations.

    Authors: Roya Beheshti, David Eisenbud
    Subjects: Algebraic Geometry
    Abstract

    We bound the complexity of the fibers of the generic linear projection of a
    smooth variety in terms of a new family of invariants. These invariants are
    closely related to ideas of John Mather, and we give a simple proof of his
    bound on the Thom-Boardman invariants of a generic projection as an
    application.

  3. Non-uniruledness results for spaces of rational curves in hypersurfaces.

    Authors: Roya Beheshti
    Subjects: Algebraic Geometry
    Abstract

    We prove that the sweeping components of the space of smooth rational curves
    in a smooth hypersurface of degree $d$ in $P^n$ are not uniruled if $(n+1)/2
    \leq d \leq n-3$. We also show that for any positive integer $e$, the space of
    smooth rational curves of degree $e$ in a general hypersurface of degree $d$ in
    $P^n$ is not uniruled when $d \geq e \sqrt{n}$.

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