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Now showing items 1-20 of 29

    • Demailly’s Notion of Algebraic Hyperbolicity: Geometricity, Boundedness, Moduli of Maps (Revised Edition) 

      [OWP-2018-20.2] Javanpeykar, Ariyan; Kamenova, Ljudmila (Mathematisches Forschungsinstitut Oberwolfach, 2020-01-23)
      Demailly's conjecture, which is a consequence of the Green-Griffths-Lang conjecture on varieties of general type, states that an algebraically hyperbolic complex projective variety is Kobayashi hyperbolic. Our aim is to ...
    • The Tutte Polynomial of Ideal Arrangements 

      [OWP-2018-28] Randriamaro, Hery (Mathematisches Forschungsinstitut Oberwolfach, 2018-12-21)
      The Tutte polynomial is originally a bivariate polynomial enumerating the colorings of a graph and of its dual graph. But it reveals more of the internal structure of the graph like its number of forests, of spanning ...
    • Spectral Continuity for Aperiodic Quantum Systems II. Periodic Approximations in 1D 

      [OWP-2018-27] Beckus, Siegfried; Bellissard, Jean; De Nittis, Giuseppe (Mathematisches Forschungsinstitut Oberwolfach, 2018-12-17)
      The existence and construction of periodic approximations with convergent spectra is crucial in solid state physics for the spectral study of corresponding Schrödinger operators. In a forthcoming work [9] this task was ...
    • Sur le Minimum de la Fonction de Brjuno 

      [OWP-2018-26] Balazard, Michel; Martin, Bruno (Mathematisches Forschungsinstitut Oberwolfach, 2018-12-11)
      The Brjuno function attains a strict global minimum at the golden section.
    • 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 ...
    • Global Variants of Hartogs' Theorem 

      [OWP-2018-24] Bochnak, Jacek; Kucharz, Wojciech (Mathematisches Forschungsinstitut Oberwolfach, 2018-11-06)
      Hartogs' theorem asserts that a separately holomorphic function, defined on an open subset of $\mathbb{C}^n$, is holomorphic in all the variables. We prove a global variant of this theorem for functions defined on an open ...
    • 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 ...
    • Computing Congruence Quotients of Zariski Dense Subgroups 

      [OWP-2018-22] Detinko, Alla; Flannery, Dane; Hulpke, Alexander (Mathematisches Forschungsinstitut Oberwolfach, 2018-10-26)
      We obtain a computational realization of the strong approximation theorem. That is, we develop algorithms to compute all congruence quotients modulo rational primes of a finitely generated Zariski dense group $H \leq ...
    • On the Invariants of the Cohomology of Complements of Coxeter Arrangements 

      [OWP-2018-21] Douglass, J. Matthew; Pfeiffer, Götz; Röhrle, Gerhard (Mathematisches Forschungsinstitut Oberwolfach, 2018-10-22)
      We refine Brieskorn's study of the cohomology of the complement of the reflection arrangement of a finite Coxeter group W. As a result we complete the verification of a conjecture by Felder and Veselov that gives an explicit ...
    • Demailly’s Notion of Algebraic Hyperbolicity: Geometricity, Boundedness, Moduli of Maps 

      [OWP-2018-20] Javanpeykar, Ariyan; Kamenova, Ljudmila (Mathematisches Forschungsinstitut Oberwolfach, 2018-10-08)
      Demailly's conjecture, which is a consequence of the Green-Griffiths-Lang conjecture on varieties of general type, states that an algebraically hyperbolic complex projective variety is Kobayashi hyperbolic. Our aim is to ...
    • Affine Space Fibrations 

      [OWP-2018-19] Gurjar, Rajendra V.; Masuda, Kayo; Miyanishi, Masayoshi (Mathematisches Forschungsinstitut Oberwolfach, 2018-09-05)
      We discuss various aspects of affine space fibrations. Our interest will be focused in the singular fibers, the generic fiber and the propagation of properties of a given smooth special fiber to nearby fibers.
    • Some Results Related to Schiffer's Problem 

      [OWP-2018-18] Kawohl, Bernd; Lucia, Marcello (Mathematisches Forschungsinstitut Oberwolfach, 2018-08-16)
      We consider the following semilinear overdetermined problem on a two dimensional bounded or unbounded domain $\Omega$ with analytic boundary $\partial\Omega$ having at least one bounded connected component \begin{eqnarray*} ...
    • 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 ...
    • 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 ...
    • An Optimal Bound for the Ratio Between Ordinary and Uniform Exponents of Diophantine Approximation 

      [OWP-2018-15] Marnat, Antoine; Moshchevitin, Nikolay (Mathematisches Forschungsinstitut Oberwolfach, 2018-07-09)
      We provide a lower bound for the ratio between the ordinary and uniform exponents of both simultaneous Diophantine approximation to n real numbers and Diophantine approximation for one linear form in n variables. This ...
    • A McKay Correspondence for Reflection Groups 

      [OWP-2018-14] Buchweitz, Ragnar-Olaf; Faber, Eleonore; Ingalls, Colin (Mathematisches Forschungsinstitut Oberwolfach, 2018-07-02)
      We construct a noncommutative desingularization of the discriminant of a finite reflection group $G$ as a quotient of the skew group ring $A=S*G$. If $G$ is generated by order two reflections, then this quotient identifies ...
    • The Magic Square of Reflections and Rotations 

      [OWP-2018-13] Buchweitz, Ragnar-Olaf; Faber, Eleonore; Ingalls, Colin (Mathematisches Forschungsinstitut Oberwolfach, 2018-07-01)
      We show how Coxeter’s work implies a bijection between complex reflection groups of rank two and real reflection groups in 0(3). We also consider this magic square of reflections and rotations in the framework of Clifford ...
    • MOSES: A Streaming Algorithm for Linear Dimensionality Reduction 

      [OWP-2018-12] Eftekhari, Armin; Hauser, Raphael A.; Grammenos, Andreas (Mathematisches Forschungsinstitut Oberwolfach, 2018-06-26)
      This paper introduces Memory-limited Online Subspace Estimation Scheme (MOSES) for both estimating the principal components of data and reducing its dimension. More specifically, consider a scenario where the data vectors ...
    • A Deformed Quon Algebra 

      [OWP-2018-11] Randriamaro, Hery (Mathematisches Forschungsinstitut Oberwolfach, 2018-06-25)
      The quon algebra is an approach to particle statistics in order to provide a theory in which the Pauli exclusion principle and Bose statistics are violated by a small amount. The quons are particles whose annihilation and ...
    • A Well-Posedness Result for Viscous Compressible Fluids with Only Bounded Density 

      [OWP-2018-10] Danchin, Raphaël; Fanelli, Francesco; Paicu, Marius (Mathematisches Forschungsinstitut Oberwolfach, 2018-05-28)
      We are concerned with the existence and uniqueness of solutions with only bounded density for the barotropic compressible Navier-Stokes equations. Assuming that the initial velocity has slightly sub-critical regularity and ...