• Boundary Conditions for Scalar Curvature 

      [OWP-2021-01] Bär, Christian; Hanke, Bernhard (Mathematisches Forschungsinstitut Oberwolfach, 2021-01-04)
      Based on the Atiyah-Patodi-Singer index formula, we construct an obstruction to positive scalar curvature metrics with mean convex boundaries on spin manifolds of infinite $K$-area. We also characterize the extremal case. ...
    • Criteria for Algebraicity of Analytic Functions 

      [OWP-2018-25] Bochnak, Jacek; Gwoździewicz, Janusz; Kucharz, Wojciech (Mathematisches Forschungsinstitut Oberwolfach, 2018-11-12)
      We consider functions defined on an open subset of a nonsingular, either real or complex, algebraic set. We give criteria for an analytic function to be a Nash (resp. regular, resp. polynomial) function. Our criteria depend ...
    • Embedding Spaces of Split Links 

      [OWP-2022-13] Boyd, Rachael; Bregman, Corey (Mathematisches Forschungsinstitut Oberwolfach, 2022-08-01)
      We study the homotopy type of the space $\mathcal{E}(L)$ of unparametrised embeddings of a split link $L=L_1\sqcup \ldots \sqcup L_n$ in $\mathbb{R}^3$. Inspired by work of Brendle and Hatcher, we introduce a semi-simplicial ...
    • An Explicit Formula for the Dirac Multiplicities on Lens Spaces 

      [OWP-2014-19] Boldt, Sebastian; Lauret, Emilio A. (Mathematisches Forschungsinstitut Oberwolfach, 2014)
      We present a new description of the spectrum of the (spin-) Dirac operator $D$ on lens spaces. Viewing a spin lens space $L$ as a locally symmetric space $\Gamma \setminus Spin(2m)/Spin(2m-1)$ and exploiting the representation ...
    • Getzler rescaling via adiabatic deformation and a renormalized local index formula 

      [OWP-2016-18] Bohlen, Karsten; Schrohe, Elmar (Mathematisches Forschungsinstitut Oberwolfach, 2016-10)
      We prove a local index theorem of Atiyah-Singer type for Dirac operators on manifolds with a Lie structure at infinity (Lie manifolds for short). After introducing a renormalized supertrace on Lie manifolds with spin ...
    • Gradient Canyons, Concentration of Curvature, and Lipschitz Invariants 

      [OWP-2017-35] Paunescu, Laurentiu; Tibăr, Mihai-Marius (Mathematisches Forschungsinstitut Oberwolfach, 2017-12-13)
      We find new bi-Lipschitz invariants of holomorphic functions of two variables by using the gradient canyons and by combining analytic and geometric viewpoints on the concentration of curvature.
    • Hight functions on quaternionic Stiefel manifolds 

      [OWP-2015-10] Macías-Virgós, Enrique; Strom, Jeffrey; Tanré, Daniel; Oprea, John (Mathematisches Forschungsinstitut Oberwolfach, 2015-07-29)
      In this note, we study height functions on quaternionic Stiefel manifolds and prove that all these height functions are Morse-Bott. Among them, we characterize the Morse functions and give a lower bound for their number ...
    • Lifting Spectral Triples to Noncommutative Principal Bundles 

      [OWP-2021-02] Schwieger, Kay; Wagner, Stefan (Mathematisches Forschungsinstitut Oberwolfach, 2021-01-11)
      Given a free action of a compact Lie group $G$ on a unital C*-algebra $\mathcal{A}$ and a spectral triple on the corresponding fixed point algebra $\mathcal{A}^G$, we present a systematic and in-depth construction of ...
    • Milnor fibre homology via deformation 

      [OWP-2015-22] Siersma, Dirk; Tibăr, Mihai-Marius (Mathematisches Forschungsinstitut Oberwolfach, 2015)
      In case of one-dimensional singular locus, we use deformations in order toget refined information about the Betti numbers of the Milnor fibre.
    • On the geometry of regular maps from a quasi-projective surface to a curve 

      [OWP-2013-03] Parameswaran, A. J.; Tibăr, Mihai-Marius (Mathematisches Forschungsinstitut Oberwolfach, 2013-03-14)
      We explore consequences of the triviality of the monodromy group, using the condition of purity of the mixed Hodge structure on the cohomology of the surface X.
    • On the δ=const Collisions of Singularities of Complex Plane Curves 

      [OWP-2008-15] Kerner, Dmitry (Mathematisches Forschungsinstitut Oberwolfach, 2008)
      We study a specific class of deformations of curve singularities: the case when the singular point splits to several ones, such that the total $\delta$ invariant is preserved. These are also known as equi-normalizable or ...
    • Real Analyticity is Concentrated in Dimension 2 

      [OWP-2018-23] Bochnak, Jacek; Kucharz, Wojciech (Mathematisches Forschungsinstitut Oberwolfach, 2018-11-05)
      We prove that a real-valued function on a real analytic manifold is analytic whenever all its restrictions to $2$-dimensional analytic submanifolds are analytic functions. We also obtain analogous results in the framework ...