• Applications of Nijenhuis Geometry III: Frobenius Pencils and Compatible Non-Homogeneous Poisson Structures 

      [OWP-2022-01] Bolsinov, Alexey V.; Konyaev, Andrey Yu.; Matveev, Vladimir S. (Mathematisches Forschungsinstitut Oberwolfach, 2022-01-20)
      We consider multicomponent local Poisson structures of the form $\mathcal P_3 + \mathcal P_1$, under the assumption that the third order term $\mathcal P_3$ is Darboux-Poisson and non-degenerate, and study the Poisson ...
    • 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. ...
    • Cluster structures on simple complex lie groups and the Belavin-Drinfeld classification 

      [OWP-2011-10] Gekhtman, Michael; Shapiro, Michael; Vainshtein, Alek (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-12)
      We study natural cluster structures in the rings of regular functions on simple complex Lie groups and Poisson-Lie structutures compatible with these cluster structures. According to our main conjecture, each class in the ...
    • 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 ...
    • Generalized Killing spinors and Lagrangian graphs 

      [OWP-2014-11] Moroianu, Andrei; Semmelmann, Uwe (Mathematisches Forschungsinstitut Oberwolfach, 2014-08-20)
      We study generalized Killing spinors on the standard sphere $\mathbb{S}^3$, which turn out to be related to Lagrangian embeddings in the nearly Kähler manifold $S^3 \times S^3$ and to great circle flows on $\mathbb{S}^3$. ...
    • Generalized Vector Cross Products and Killing Forms on Negatively Curved Manifolds 

      [OWP-2018-17] Barberis, María Laura; Moroianu, Andrei; Semmelmann, Uwe (Mathematisches Forschungsinstitut Oberwolfach, 2018-07-17)
      Motivated by the study of Killing forms on compact Riemannian manifolds of negative sectional curvature, we introduce the notion of generalized vector cross products on $\mathbb{R}^n$ and give their classification. Using ...
    • A Gentle Introduction to Interpolation on the Grassmann Manifold 

      [OWP-2024-02] Ciaramella, Gabriele; Gander, Martin J.; Vanzan, Tommaso (Mathematisches Forschungsinstitut Oberwolfach, 2024-01-10)
    • 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 ...
    • Invariant Four-forms and Symmetric Pairs 

      [OWP-2012-03] Moroianu, Andrei; Semmelmann, Uwe (Mathematisches Forschungsinstitut Oberwolfach, 2012-04-24)
      We give criteria for real, complex and quaternionic representations to define $s$-representations, focusing on exceptional Lie algebras defined by spin representations. As applications, we obtain the classification of ...
    • Killing Tensors on Tori 

      [OWP-2016-20] Heil, Konstantin; Moroianu, Andrei; Semmelmann, Uwe (Mathematisches Forschungsinstitut Oberwolfach, 2016-11-10)
      We show that Killing tensors on conformally at n-dimensional tori whose conformal factor only depends on one variable, are polynomials in the metric and in the Killing vector fields. In other words, every first integral ...
    • Legendrian Lens Space Surgeries 

      [OWP-2016-10] Geiges, Hansjörg; Onaran, Sinem (Mathematisches Forschungsinstitut Oberwolfach, 2016-06-17)
      We show that every tight contact structure on any of the lens spaces $L(ns^2 - s + 1,s^2)$ with $n\geq 2, s \geq 1$, can be obtained by a single Legendrian surgery along a suitable Legendrian realisation of the negative ...
    • Legendrian rational unknots in lens spaces 

      [OWP-2013-06] Geiges, Hansjörg; Onaran, Sinem (Mathematisches Forschungsinstitut Oberwolfach, 2013-03-14)
      We classify Legendrian rational unknots with tight complements in the lens spaces $L(p,1)$ up to coarse equivalence. As an example of the general case, this classification is also worked out for $L(5, 2)$. The knots are ...
    • Locally conformally Kähler manifolds admitting a holomorphic conformal flow 

      [OWP-2010-13] Ornea, Liviu; Verbitsky, Misha (Mathematisches Forschungsinstitut Oberwolfach, 2010-03-15)
      A manifold $M$ is locally conformally Kähler (LCK) if it admits a Kähler covering $\tilde{M}$ with monodromy acting by holomorphic homotheties. Let $M$ be an LCK manifold admitting a holomorphic conformal flow of ...
    • Metric Connections with Parallel Skew-Symmetric Torsion 

      [OWP-2018-16] Cleyton, Richard; Moroianu, Andrei; Semmelmann, Uwe (Mathematisches Forschungsinstitut Oberwolfach, 2018-07-16)
      A geometry with parallel skew-symmetric torsion is a Riemannian manifold carrying a metric connection with parallel skew-symmetric torsion. Besides the trivial case of the Levi-Civita connection, geometries with non-vanishing ...
    • Minimal Codimension One Foliation of a Symmetric Space by Damek-Ricci Spaces 

      [OWP-2019-11] Knieper, Gerhard; Parker, John R.; Peyerimhoff, Norbert (Mathematisches Forschungsinstitut Oberwolfach, 2019-05-07)
      In this article we consider solvable hypersurfaces of the form $N \exp(\mathbb{R} H)$ with induced metrics in the symmetric space $M = SL(3,\mathbb{C})/SU(3)$, where $H$ a suitable unit length vector in the subgroup $A$ ...
    • Noncompact harmonic manifolds 

      [OWP-2013-08] Knieper, Gerhard; Peyerimhoff, Norbert (Mathematisches Forschungsinstitut Oberwolfach, 2013-04-10)
      The Lichnerowicz conjecture asserts that all harmonic manifolds are either flat or locally symmetric spaces of rank 1. This conjecture has been proved by Z.I. Szab ́o [Sz] for harmonic manifolds with compact universal ...
    • On the autonomous metric on groups of Hamiltonian diffeomorphisms of closed hyperbolic surfaces 

      [OWP-2013-18] Brandenbursky, Michael (Mathematisches Forschungsinstitut Oberwolfach, 2013-07-23)
      Let $\Sigma_g$ be a closed hyperbolic surface of genus $g$ and let Ham($\Sigma_ g$) be the group of Hamiltonian diffeomorphisms of $\Sigma_g$. The most natural word metric on this group is the autonomous metric. It has ...
    • A Quantitative Analysis of the “Lion-Man” Game 

      [OWP-2019-18] Kohlenbach, Ulrich; López-Acedo, Genaro; Nicolae, Adriana (Mathematisches Forschungsinstitut Oberwolfach, 2019-07-08)
      In this paper we analyze, based on an interplay between ideas and techniques from logic and geometric analysis, a pursuit-evasion game. More precisely, we focus on a discrete lion and man game with an $\varepsilon$-capture ...
    • Singularities and Bifurcations of Pseudospherical Surfaces 

      [OWP-2020-08] Brander, David; Tari, Farid (Mathematisches Forschungsinstitut Oberwolfach, 2020-03-17)
      We study singularities and bifurcations of constant negative curvature surfaces in Euclidean 3-space via their association with Lorentzian harmonic maps. This preprint presents the basic results on this, the full proofs ...
    • Weakly Complex Homogeneous Spaces 

      [OWP-2012-04] Moroianu, Andrei; Semmelmann, Uwe (Mathematisches Forschungsinstitut Oberwolfach, 2012-04-24)
      We complete our recent classification of compact inner symmetric spaces with weakly complex tangent bundle by filling up a case which was left open, and extend this classification to the larger category of compact homogeneous ...