• 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 ...
    • On the autonomous metric on the group of area-preserving diffeomorphisms of the 2-disc 

      [OWP-2012-16] Brandenbursky, Michael; Kȩdra, Jarek (Mathematisches Forschungsinstitut Oberwolfach, 2012)
      Let $D^2$ be the open unit disc in the Euclidean plane and let $G := Diff(D^2; area)$ be the group of smooth compactly supported area-preserving diffeomorphisms of $D^2$. For every natural number $k$ we construct an injective ...
    • On the complement of the dense orbit for a quiver of type A 

      [OWP-2010-11] Baur, Karin; Hille, Lutz (Mathematisches Forschungsinstitut Oberwolfach, 2010)
      Let $\mathbb{A}_t$ be the directed quiver of type $A$ with $t$ vertices. For each dimension vector $d$ there is a dense orbit in the corresponding representation space. The principal aim of this note is to use just rank ...
    • On the Complement of the Richardson Orbit 

      [OWP-2010-09] Baur, Karin; Hille, Lutz (Mathematisches Forschungsinstitut Oberwolfach, 2010-03-13)
      We consider parabolic subgroups of a general algebraic group over an algebraically closed field $k$ whose Levi part has exactly $t$ factors. By a classical theorem of Richardson, the nilradical of a parabolic subgroup $P$ ...
    • On the Derived Category of Grassmannians in Arbitrary Characteristic 

      [OWP-2013-24] Buchweitz, Ragnar-Olaf; Leuschke, Graham J.; Van den Bergh, Michel (Mathematisches Forschungsinstitut Oberwolfach, 2013-12-09)
      In this paper we consider Grassmannians in arbitrary characteristic. Generalizing Kapranov's well-known characteristic-zero results we construct dual exceptional collections on them (which are however not strong) as well ...
    • On the Directionally Newton-non-degenerate Singularities of Complex Hypersurfaces 

      [OWP-2008-16] Kerner, Dmitry (Mathematisches Forschungsinstitut Oberwolfach, 2008)
      We introduce a minimal generalization of Newton-non-degenerate singularities of hypersurfaces. Roughly speaking, an isolated hypersurface singularity is called directionally Newton-non-degenerate if the local embedded ...
    • On the distribution of a second class particle in the asymmetric simple exclusion process 

      [OWP-2009-22] Tracy, Craig A.; Widom, Harold (Mathematisches Forschungsinstitut Oberwolfach, 2009-03-15)
      We give an exact expression for the distribution of the position $X(t)$ of a single second class particle in the asymmetric simple exclusion process (ASEP) where initially the second class particle is located at the origin ...
    • 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 $S=K[x_1,\ldots,x_d]$ of dimension $d$, generated by finitely many monomials of degree $r$. Then the Gauss algebra $\mathbb{G}(A)$ of $A$ is generated by monomials of ...
    • 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 geometry of the space of fibrations 

      [OWP-2009-15] Humilière, Vincent; Roy, Nicolas (Mathematisches Forschungsinstitut Oberwolfach, 2009-03-09)
      We study geometrical aspects of the space of fibrations between two given manifolds $M$ and $B$, from the point of view of Fréchet geometry. As a first result, we show that any connected component of this space is the ...
    • 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 ...
    • On the L2 Markov Inequality with Laguerre Weight 

      [OWP-2016-15] Nikolov, Geno P.; Shadrin, Alexei (Mathematisches Forschungsinstitut Oberwolfach, 2016-08-17)
    • On the Lie Algebra Structure of $HH^1(A)$ of a Finite-Dimensional Algebra A 

      [OWP-2019-10] Linckelmann, Markus; Rubio y Degrassi, Lleonard (Mathematisches Forschungsinstitut Oberwolfach, 2019-04-17)
      Let $A$ be a split finite-dimensional associative unital algebra over a field. The first main result of this note shows that if the Ext-quiver of $A$ is a simple directed graph, then $HH^1(A)$ is a solvable Lie algebra. ...
    • On the Markov inequality in the $L_2$-norm with the Gegenbauer weight 

      [OWP-2017-05] Nikolov, Geno P.; Shadrin, Alexei (Mathematisches Forschungsinstitut Oberwolfach, 2017-02-22)
      Let $w_{\lambda}(t) := (1-t^2)^{\lambda-1/2}$, where ${\lambda} > -\frac{1}{2}$, be the Gegenbauer weight function, let $\|\cdot\|_{w_{\lambda}}$ be the associated $L_2$-norm, $$ |f\|_{w_{\lambda}} = \left\{\int_{-1}^1 ...
    • On the non-analyticity locus of an arc-analytic function 

      [OWP-2009-03] Kurdyka, Krzysztof; Parusinski, Adam (Mathematisches Forschungsinstitut Oberwolfach, 2009-02-21)
      A function is called arc-analytic if it is real analytic on each real analytic arc. In real analytic geometry there are many examples of arc-analytic functions that are not real analytic. Arc analytic functions appear ...
    • On the prediction of stationary functional time series 

      [OWP-2014-06] Aue, Alexander; Dubart Norinho, Diogo; Hörmann, Siegfried (Mathematisches Forschungsinstitut Oberwolfach, 2014-04-25)
      This paper addresses the prediction of stationary functional time series. Existing contributions to this problem have largely focused on the special case of first-order functional autoregressive processes because of their ...
    • 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 ...
    • On Unipotent Radicals of Pseudo-Reductive Groups 

      [OWP-2017-12] Bate, Michael; Martin, Benjamin; Röhrle, Gerhard; Stewart, David I. (Mathematisches Forschungsinstitut Oberwolfach, 2017-04-27)
      We establish some results on the structure of the geometric unipotent radicals of pseudo-reductive k-groups. In particular, let $k'$ be a purely inseparable field extension of k of degree $p^e$ and let $G$ denote the ...
    • On Vietoris-Rips Complexes of Ellipses 

      [OWP-2017-11] Adamaszek, Michal; Adams, Henry; Reddy, Samadwara (Mathematisches Forschungsinstitut Oberwolfach, 2017-04-25)
      For $X$ a metric space and $r > 0$ a scale parameter, the Vietoris–Rips complex $VR_<(X; r)$ (resp. $VR_≤(X; r)$) has $X$ as its vertex set, and a finite subset $\sigma \subseteq X$ as a simplex whenever the diameter of ...
    • On Weak Weighted Estimates of Martingale Transform 

      [OWP-2016-22] Nazarov, Fedor; Reznikov, Alexander; Vasyunin, Vasily; Volberg, Alexander (Mathematisches Forschungsinstitut Oberwolfach, 2016-11-12)
      We consider several weak type estimates for singular operators using the Bellman function approach. We disprove the $A_1$ conjecture, which stayed open after Muckenhoupt-Wheeden's conjecture was disproved by Reguera-Thiele.