Alexander I. Suciu

  1. Resonance varieties and Dwyer-Fried invariants.

    Authors: Alexander I. Suciu
    Subjects: Algebraic Geometry
    Abstract

    The Dwyer-Fried invariants of a finite cell complex X are the subsets
    \Omega^i_r(X) of the Grassmannian of r-planes in H^1(X,\Q) which parametrize
    the regular \Z^r-covers of X having finite Betti numbers up to degree i. In
    previous work, we showed that each \Omega-invariant is contained in the
    complement of a union of Schubert varieties associated to a certain subspace
    arrangement in H^1(X,\Q). Here, we identify a class of spaces for which this
    inclusion holds as equality.

  2. Quasi-K\"ahler groups, 3-manifold groups, and formality.

    Authors: Alexandru Dimca, Alexander I. Suciu, Stefan Papadima
    Subjects: Algebraic Geometry
    Abstract

    In this note, we address the following question: Which 1-formal groups occur
    as fundamental groups of both quasi-K\"ahler manifolds and closed, connected,
    orientable 3-manifolds. We classify all such groups, at the level of Malcev
    completions, and compute their coranks. Dropping the assumption on
    realizability by 3-manifolds, we show that the corank equals the isotropy index
    of the cup-product map in degree one. Finally, we examine the formality
    properties of smooth affine surfaces and quasi-homogeneous isolated surface
    singularities.

  3. Fundamental groups, Alexander invariants, and cohomology jumping loci.

    Authors: Alexander I. Suciu
    Subjects: Geometric Topology
    Abstract

    We survey the cohomology jumping loci and the Alexander-type invariants
    associated to a space, or to its fundamental group. Though most of the material
    is expository, we provide new examples and applications, which in turn raise
    several questions and conjectures.

  4. Fundamental groups, Alexander invariants, and cohomology jumping loci.

    Authors: Alexander I. Suciu
    Subjects: Geometric Topology
    Abstract

    We survey the cohomology jumping loci and the Alexander-type invariants
    associated to a space, or to its fundamental group. Though most of the material
    is expository, we provide new examples and applications, which in turn raise
    several questions and conjectures.

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