Auflistung 2013 nach Titel
Anzeige der Dokumente 17-28 von 28
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Obtaining Error-Minimizing Estimates and Universal Entry-Wise Error Bounds for Low-Rank Matrix Completion
[OWP-2013-12] (Mathematisches Forschungsinstitut Oberwolfach, 2013-06-10)We propose a general framework for reconstructing and denoising single entries of incomplete and noisy entries. We describe: effective algorithms for deciding if and entry can be reconstructed and, if so, for reconstructing ... -
On Concentrators and Related Approximation Constants
[OWP-2013-14] (Mathematisches Forschungsinstitut Oberwolfach, 2013-06-10)Pippenger ([Pip77]) showed the existence of (6m, 4m, 3m, 6)-concentrator for each positive integer m using a probabilistic method. We generalize his approach and prove existence of (6m, 4m, 3m, 5.05)-concentrator (which ... -
On conjugacy of MASAs and the outer automorphism group of the Cuntz algebra
[OWP-2013-21] (Mathematisches Forschungsinstitut Oberwolfach, 2013-10-29)We investigate the structure of the outer automorphism group of the Cuntz algebra and the closely related problem of conjugacy of MASAa in $\mathcal{O}_n$. In particular, we exhibit an uncountable family of MASAs, conjugate ... -
On the autonomous metric on groups of Hamiltonian diffeomorphisms of closed hyperbolic surfaces
[OWP-2013-18] (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 Derived Category of Grassmannians in Arbitrary Characteristic
[OWP-2013-24] (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 geometry of regular maps from a quasi-projective surface to a curve
[OWP-2013-03] (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. -
A Relation Between N-Qubit and 2N-1-Qubit Pauli Groups via Binary LGr(N,2N)
[OWP-2013-25] (Mathematisches Forschungsinstitut Oberwolfach, 2013-12-09)Employing the fact that the geometry of the $N$-qubit ($N\geq 2$) Pauli group is embodied in the structure of the symplectic polar space $\mathcal{W}(2N-1, 2)$ and using properties of the Lagrangian Grassmannian $LGr(N, ... -
Right Simple Singularities in Positive Characteristic
[OWP-2013-28] (Mathematisches Forschungsinstitut Oberwolfach, 2013)We classify isolated singularities $f \in K[[x_1,...,x_n]]$, which are simple, i.e. have no moduli, w.r.t. right equivalence, where $K$ is an algebraically closed field of characteristic $p>0$. For $K=\mathbb{R}$ or ... -
Sharp constants in the classical weak form of the John-Nirenberg inequality
[OWP-2013-07] (Mathematisches Forschungsinstitut Oberwolfach, 2013-03-14)The sharp constants in the classical John-Nirenberg inequality are found by using Bellman function approach. -
Solid extensions of the Cesàro operator on the Hardy space H2(D)
[OWP-2013-11] (Mathematisches Forschungsinstitut Oberwolfach, 2013-04-23)We introduce and study the largest Banach space of analytic functions on the unit disc which is solid for the coefficient-wise order and to which the classical Ces`aro operator $\mathcal{C}:H^2 \to H^2$ can be continuously ... -
Supertropical Quadratic Forms I
[OWP-2013-27] (Mathematisches Forschungsinstitut Oberwolfach, 2013)We initiate the theory of a quadratic form q over a semiring $R$. As customary, one can write $q(x+y)=q(x)+q(y)+b(x,y)$, where b is a companion bilinear form. But in contrast to the ring-theoretic case, the companion ... -
Very general monomial valuations of P2 and a Nagata type conjecture
[OWP-2013-22] (Mathematisches Forschungsinstitut Oberwolfach, 2013-10-29)