• 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.
    • Categorical Linearly Ordered Structures 

      [OWP-2018-08] Downey, Rod; Melnikov, Alexander; Ng, Keng Meng (Mathematisches Forschungsinstitut Oberwolfach, 2018-04-26)
      We prove that for every computable limit ordinal α there exists a computable linear ordering A which is Δ0α-categorical and α is smallest such, but nonetheless for every isomorphic ...
    • 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 ...
    • 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 ...
    • Deformation Classification of Real Non-Singular Cubic Threefolds with a Marked Line 

      [OWP-2018-02] Finashin, Sergey; Kharlamov, Viatcheslav (Mathematisches Forschungsinstitut Oberwolfach, 2018-02-21)
      We prove that the space of pairs (X,l) formed by a real non-singular cubic hypersurface XP4 with a real line lX has 18 connected components and give for them several quite explicit interpretations. ...
    • 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 ...
    • Demailly’s Notion of Algebraic Hyperbolicity: Geometricity, Boundedness, Moduli of Maps 

      [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 ...
    • 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 ...
    • Exceptional Legendrian Torus Knots 

      [OWP-2018-04] Geiges, Hansjörg; Onaran, Sinem (Mathematisches Forschungsinstitut Oberwolfach, 2018-03-21)
      We present classification results for exceptional Legendrian realisations of torus knots. These are the first results of that kind for non-trivial topological knot types. Enumeration results of Ding-Li-Zhang concerning ...
    • 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 Rn and give their classification. Using ...
    • 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 Cn, is holomorphic in all the variables. We prove a global variant of this theorem for functions defined on an open ...
    • Herbrand’s Theorem as Higher Order Recursion 

      [OWP-2018-01] Afshari, Bahareh; Hetzl, Stefan; Leigh, Graham E. (Mathematisches Forschungsinstitut Oberwolfach, 2018-02-19)
      We provide a means to compute Herbrand disjunctions directly from sequent calculus proofs with cuts. Our approach associates to a first-order classical proof πvF, where F is quantifier free, an ...
    • Homogenization of a nonlinear monotone problem with nonlinear Signorini boundary conditions in a domain with highly rough boundary 

      [OWP-2018-06] Gaudiello, Antonio; Mel'nyk, Taras A. (Mathematisches Forschungsinstitut Oberwolfach, 2018-04-16)
      We consider a domain ΩεRN, N2, with a very rough boundary depending on~ε. For instance, if N=3 the domain Ωε has the form of a brush with an ...
    • 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 ...
    • The Martin Boundary of Relatively Hyperbolic Groups with Virtually Abelian Parabolic Subgroups 

      [OWP-2018-03] Dussaule, Matthieu; Gekhtman, Ilya; Gerasimov, Victor; Potyagailo, Leonid (Mathematisches Forschungsinstitut Oberwolfach, 2018-03-19)
      Given a probability measure on a finitely generated group, its Martin boundary is a way to compactify the group using the Green's function of the corresponding random walk. We give a complete topological characterization ...
    • Max-Linear Models on Infinite Graphs Generated by Bernoulli Bond Percolation 

      [OWP-2018-09] Klüppelberg, Claudia; Sönmez, Ercan (Mathematisches Forschungsinstitut Oberwolfach, 2018-05-17)
      We extend previous work of max-linear models on finite directed acyclic graphs to infinite graphs, and investigate their relations to classical percolation theory. We formulate results for the oriented square lattice graph ...
    • 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=SG. If G is generated by order two reflections, then this quotient identifies ...
    • 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 ...
    • 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 ...
    • On the Gauss Algebra of Toric Algebras 

      [OWP-2018-07] Herzog, Jürgen; Jafari, Raheleh; Nasrollah Nejad, Abbas (Mathematisches Forschungsinstitut Oberwolfach, 2018-04-25)
      Let A be a K-subalgebra of the polynomial ring S=K[x1,,xd] of dimension d, generated by finitely many monomials of degree r. Then the Gauss algebra G(A) of A is generated by monomials of ...