Browsing by Issue Date

Now showing items 1701-1720 of 1987

    • 2046 - Mathematical Logic: Proof Theory, Constructive Mathematics (hybrid meeting) 

      [OWR-2020-34] (2020) - (08 Nov - 14 Nov 2020)
      The Workshop "Mathematical Logic: Proof Theory, Constructive Mathematics" focused on proofs both as formal derivations in deductive systems as well as on the extraction of explicit computational content from given ...

    • 2007 - Manifolds and Groups 

      [OWR-2020-7] (2020) - (09 Feb - 15 Feb 2020)
      The workshop concentrated on the interplay of advances in the understanding of manifolds and geometric group theory. In particular, we discussed mapping class groups and moduli spaces of manifolds (also of high ...

    • 2037a - Topological and Smooth Dynamics on Surfaces (individual research only) 

      [OWR-2020-27] (2020) - (06 Sep - 12 Sep 2020)
      Because of the pandemia, the workshop on "Topological and Smooth Dynamics on Surfaces" could not be realized in the usual format or in the new hybrid format. Instead, a subgroup of 3 participants used the week mostly ...

    • Das ternäre Goldbach-Problem 

      [SNAP-2014-003-DE] Helfgott, Harald (Mathematisches Forschungsinstitut Oberwolfach, 2020)
      Leonhard Euler (1707–1783) war einer der besten Mathematiker des 18. Jahrhunderts und wohl auch aller Zeiten. Er korrespondierte oft mit seinem Freund, Christoph Goldbach (1690–1764), einem Universalgelehrten, der auch ...

    • 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 ...

    • Positive Line Bundles Over the Irreducible Quantum Flag Manifolds 

      [OWP-2020-01] Díaz García, Fredy; Krutov, Andrey; Ó Buachalla, Réamonn; Somberg, Petr; Strung, Karen R. (Mathematisches Forschungsinstitut Oberwolfach, 2020-02-03)
      Noncommutative Kähler structures were recently introduced by the third author as a framework for studying noncommutative Kähler geometry on quantum homogeneous spaces. It was subsequently observed that the notion of a ...

    • Nondegenerate Invariant Symmetric Bilinear Forms on Simple Lie Superalgebras in Characteristic 2 

      [OWP-2020-02] Krutov, Andrey; Lebedev, Alexei; Leites, Dimitry; Shchepochkina, Irina (Mathematisches Forschungsinstitut Oberwolfach, 2020-02-04)
      As is well-known, the dimension of the space of non-degenerate invariant symmetric bilinear forms (NISes) on any simple finite-dimensional Lie algebra or Lie superalgebra is equal to at most 1 if the characteristic of the ...

    • Splitting Necklaces, with Constraints 

      [OWP-2020-03] Jojic, Dusko; Panina, Gaiane; Zivaljevic, Rade (Mathematisches Forschungsinstitut Oberwolfach, 2020-02-11)
      We prove several versions of Alon's "necklace-splitting theorem", subject to additional constraints, as illustrated by the following results. (1) The "almost equicardinal necklace-splitting theorem" claims that, without ...

    • Multivariate Hybrid Orthogonal Functions 

      [OWP-2020-04] Bracciali, Cleonice F.; Pérez, Teresa E. (Mathematisches Forschungsinstitut Oberwolfach, 2020-03-12)
      We consider multivariate orthogonal functions satisfying hybrid orthogonality conditions with respect to a moment functional. This kind of orthogonality means that the product of functions of different parity order ...

    • Rational Functions with Small Value Set 

      [OWP-2020-05] Bartoli, Daniele; Borges, Herivelto; Quoos, Luciane (Mathematisches Forschungsinstitut Oberwolfach, 2020-03-14)
      In connection with Galois Theory and Algebraic Curves, this paper investigates rational functions $h(x) = f(x)/g(x) \in \mathbb{F}_q(x)$ for which the value set $V_h = {\{h(α) | α \in \mathbb{F}_q \cup\{\infty\}}\}$ is ...

    • Nonexistence of Subcritical Solitary Waves 

      [OWP-2020-06] Kozlov, Vladimir; Lokharu, Evgeniy; Wheeler, Miles H. (Mathematisches Forschungsinstitut Oberwolfach, 2020-03-15)
      We prove the nonexistence of two-dimensional solitary gravity water waves with subcritical wave speeds and an arbitrary distribution of vorticity. This is a longstanding open problem, and even in the irrotational case there ...

    • Generating Finite Coxeter Groups with Elements of the Same Order 

      [OWP-2020-07] Hart, Sarah; Kelsey, Veronica; Rowley, Peter (Mathematisches Forschungsinstitut Oberwolfach, 2020-03-16)
      Supposing $G$ is a group and $k$ a natural number, $d_k(G)$ is defined to be the minimal number of elements of $G$ of order $k$ which generate $G$ (setting $d_k(G) = 0$ if $G$ has no such generating sets). This paper ...

    • 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 ...

    • Theoretical Analysis and Simulation Methods for Hawkes Processes and their Diffusion Approximation 

      [OWP-2020-09] Chevallier, Julien; Melnykova, Anna; Tubikanec, Irene (Mathematisches Forschungsinstitut Oberwolfach, 2020-03-30)
      Oscillatory systems of interacting Hawkes processes with Erlang memory kernels were introduced in Ditlevsen and Löcherbach (2017). They are piecewise deterministic Markov processes (PDMP) and can be approximated by a ...

    • Vertex-to-self trajectories on the platonic solids 

      [SNAP-2020-003-EN] Athreya, Jayadev S.; Aulicino, David (Mathematisches Forschungsinstitut Oberwolfach, 2020-04-15)
      We consider the problem of walking in a straight line on the surface of a Platonic solid. While the tetrahedron, octahedron, cube, and icosahedron all exhibit the same behavior, we find a remarkable difference with the ...

    • From Betti numbers to ℓ²-Betti numbers 

      [SNAP-2020-001-EN] Kammeyer, Holger; Sauer, Roman (Mathematisches Forschungsinstitut Oberwolfach, 2020-04-15)
      We provide a leisurely introduction to ℓ²-Betti numbers, which are topological invariants, by relating them to their much older cousins, Betti numbers. In the end we present an open research problem about ℓ²-Betti numbers.

    • Random matrix theory: Dyson Brownian motion 

      [SNAP-2020-002-EN] Finocchio, Gianluca (Mathematisches Forschungsinstitut Oberwolfach, 2020-04-15)
      The theory of random matrices was introduced by John Wishart (1898–1956) in 1928. The theory was then developed within the field of nuclear physics from 1955 by Eugene Paul Wigner (1902–1995) and later by Freeman John ...

    • Determinacy versus indeterminacy 

      [SNAP-2020-004-EN] Berg, Christian (Mathematisches Forschungsinstitut Oberwolfach, 2020-04-22)
      Can a continuous function on an interval be uniquely determined if we know all the integrals of the function against the natural powers of the variable? Following Weierstrass and Stieltjes, we show that the answer is yes ...

    • On Weakly Complete Universal Enveloping Algebras of pro-Lie Algebras 

      [OWP-2020-10] Hofmann, Karl Heinrich; Kramer, Linus (Mathematisches Forschungsinstitut Oberwolfach, 2020-04-27)

    • l-Torsion Bounds for the Class Group of Number Fields with an l -Group as Galois Group 

      [OWP-2020-11] Klüners, Jürgen; Wang, Jiuya (Mathematisches Forschungsinstitut Oberwolfach, 2020-05-04)
      We describe the relations among the $\ell$-torsion conjecture for $\ell$-extensions, the discriminant multiplicity conjecture for nilpotent extensions and a conjecture of Malle giving an upper bound for the number of ...