Browsing 2012 by Title
Now showing items 8-19 of 19
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K-Triviality, Oberwolfach randomness, and differentiability
[OWP-2012-17] (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 ... -
Module Categories for Group Algebras over Commutative Rings
[OWP-2012-12] (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 ... -
On commuting varieties of nilradicals of Borel subalgebras of reductive Lie algebras
[OWP-2012-14] (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 $\mathfrak{u}$ ... -
On the autonomous metric on the group of area-preserving diffeomorphisms of the 2-disc
[OWP-2012-16] (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 ... -
Polynomiality, wall crossings and tropical geometry of rational double hurwitz cycles
[OWP-2012-13] (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 ... -
Positive Margins and Primary Decomposition
[OWP-2012-06] (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] (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 ... -
A real algebra perspective on multivariate tight wavelet frames
[OWP-2012-11] (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] (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 ... -
Strongly Consistent Density Estimation of Regression Redidual
[OWP-2012-07] (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 ... -
A Uniform Model for Kirillov-Reshetikhin Crystals I: Lifting the Parabolic Quantum Bruhat Graph
[OWP-2012-18] (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 ... -
Weakly Complex Homogeneous Spaces
[OWP-2012-04] (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 ...