Recent Submissions

  • 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 ...
  • Invariants of Closed Braids via Counting Surfaces 

    [OWP-2012-15] Brandenbursky, Michael (Mathematisches Forschungsinstitut Oberwolfach, 2012)
    A Gauss diagram is a simple, combinatorial way to present a link. It is known that any Vassiliev invariant may be obtained from a Gauss diagram formula that involves counting subdiagrams of certain combinatorial types. In ...
  • Positive Margins and Primary Decomposition 

    [OWP-2012-06] Kahle, Thomas; Rauh, Johannes; Sullivant, Seth (Mathematisches Forschungsinstitut Oberwolfach, 2012)
    We study random walks on contingency tables with fixed marginals, corresponding to a (log-linear) hierarchical model. If the set of allowed moves is not a Markov basis, then there exist tables with the same marginals that ...
  • Rate of Convergence of the Density Estimation of Regression Residual 

    [OWP-2012-08] Györfi, László; Walk, Harro (Mathematisches Forschungsinstitut Oberwolfach, 2012)
    Consider the regression problem with a response variable $Y$ and with a $d$-dimensional feature vector $X$. For the regression function $m(x) = \mathbb{E}\{Y|X = x\}$, this paper investigates methods for estimating the ...
  • Strongly Consistent Density Estimation of Regression Redidual 

    [OWP-2012-07] Györfi, László; Walk, Harro (Mathematisches Forschungsinstitut Oberwolfach, 2012)
    Consider the regression problem with a response variable $Y$ and with a $d$-dimensional feature vector $X$. For the regression function $m(x) = \mathbb{E}\{Y|X = x\}$, this paper investigates methods for estimating the ...
  • Contractive Idempotents on Locally Compact Quantum Groups 

    [OWP-2012-19] Neufang, Matthias; Salmi, Pekka; Skalski, Adam; Spronk, Nico (Mathematisches Forschungsinstitut Oberwolfach, 2012)
    A general form of contractive idempotent functionals on coamenable locally compact quantum groups is obtained, generalising the result of Greenleaf on contractive measures on locally compact groups. The image of a convolution ...
  • A Uniform Model for Kirillov-Reshetikhin Crystals I: Lifting the Parabolic Quantum Bruhat Graph 

    [OWP-2012-18] Lenart, Cristian; Naito, Satoshi; Sagaki, Daisuke; Schilling, Anne; Shimozono, Mark (Mathematisches Forschungsinstitut Oberwolfach, 2012)
    We consider two lifts of the parabolic quantum Bruhat graph, one into the Bruhat order in the affine Weyl group and the other into a level-zero weight poset first considered by Littelmann. The lift into the affine Weyl ...
  • K-Triviality, Oberwolfach randomness, and differentiability 

    [OWP-2012-17] Bienvenu, Laurent; Greenberg, Noam; Kučera, Antonin; Nies, André; Turetsky, Dan (Mathematisches Forschungsinstitut Oberwolfach, 2012-12-21)
    We show that a Martin-Lof random set for which the effective version of the Lebesgue density theorem fails computes every $K$-trivial set. Combined with a recent result by Day and Miller, this gives a positive solution to ...
  • On commuting varieties of nilradicals of borel subalgebras of reductive lie algebras 

    [OWP-2012-14] Goodwin, Simon M.; Röhrle, Gerhard (Mathematisches Forschungsinstitut Oberwolfach, 2012-12-04)
    Let $G$ be a connected reductive algebraic group defined over an algebraically closed field $\mathbb{k}$ of characteristic zero. We consider the commuting variety $\mathcal{C}(\mathfrak{u})$ of the nilradical $\mathfrak{u}$ ...
  • Polynomiality, wall crossings and tropical geometry of rational double hurwitz cycles 

    [OWP-2012-13] Bertram, Aaron; Cavalieri, Renzo; Markwig, Hannah (Mathematisches Forschungsinstitut Oberwolfach, 2012-12-04)
    We study rational double Hurwitz cycles, i.e. loci of marked rational stable curves admitting a map to the projective line with assigned ramification profiles over two fixed branch points. Generalizing the phenomenon ...
  • Module Categories for Group Algebras over Commutative Rings 

    [OWP-2012-12] Benson, David J.; Iyengar, Srikanth B.; Krause, Henning; Stevenson, Greg (Mathematisches Forschungsinstitut Oberwolfach, 2012-10-01)
    We develop a suitable version of the stable module category of a finite group $G$ over an arbitrary commutative ring $k$. The purpose of the construction is to produce a compactly generated triangulated category whose ...
  • A real algebra perspective on multivariate tight wavelet frames 

    [OWP-2012-11] Charina, Maria; Putinar, Mihai; Scheiderer, Claus; Stöckler, Joachim (Mathematisches Forschungsinstitut Oberwolfach, 2012-08-13)
    Recent results from real algebraic geometry and the theory of polynomial optimization are related in a new framework to the existence question of multivariate tight wavelet frames whose generators have at least one vanishing ...
  • Spatial-Skin Effect for a Spectral Problem with "Slightly Heavy" Concentrated Masses in a Thick Cascade Junction 

    [OWP-2012-10] Čečkin, Grigorij A.; Mel'nyk, Taras A. (Mathematisches Forschungsinstitut Oberwolfach, 2012-07-03)
    The asymptotic behavior (as $\varepsilon \to 0$) of eigenvalues and eigenfunctions of a boundary- value problem for the Laplace operator in a thick cascade junction with concentrated masses is studied. This cascade junction ...
  • Ghost Algebras of Double Burnside Algebras via Schur Functors 

    [OWP-2012-09] Boltje, Robert; Danz, Susanne (Mathematisches Forschungsinstitut Oberwolfach, 2012-07-03)
    For a finite group $G$, we introduce a multiplication on the $\mathbb{Q}$-vector space with basis $\mathscr{S}_{G\times G}$, the set of subgroups of ${G \times G}$. The resulting $\mathbb{Q}$-algebra $\tilde{A}$ can be ...
  • Categoric Aspects of Authentication 

    [OWP-2012-05] Schillewaert, Jeroen; Thas, Koen (Mathematisches Forschungsinstitut Oberwolfach, 2012-04-24)
  • 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 ...
  • 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 ...
  • Commuting Differential Operators and Higher-dimensional Algebraic Varieties 

    [OWP-2012-02] Kurke, Herbert; Osipov, Denis; Zheglov, Alexander (Mathematisches Forschungsinstitut Oberwolfach, 2012-03-20)
    Several algebro-geometric properties of commutative rings of partial differential operators as well as several geometric constructions are investigated.
  • Cryptanalysis of Public-key Cryptosystems Based on Algebraic Geometry Codes 

    [OWP-2012-01] Márquez-Corbella, Irene; Martínez-Moro, Edgar; Pellikaan, Ruud (Mathematisches Forschungsinstitut Oberwolfach, 2012-03-20)
    This paper addresses the question of retrieving the triple $(\mathcal{X},\mathcal{P},\mathcal{E})$ from the algebraic geometry code $\mathcal{C}_L(\mathcal{X},\mathcal{P},\mathcal{E})$, where $\mathcal{X}$ is an algebraic ...