Search
Now showing items 1-10 of 28
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 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 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 ...
Even-homogeneous supermanifolds on the complex projective line
[OWP-2013-02] (Mathematisches Forschungsinstitut Oberwolfach, 2013-03-14)
The classification of even-homogeneous complex supermanifolds of dimension $1|m$, $m<=3$, on $\mathbb{CP}^1$ up to isomorphism is given. An explicit description of such supermanifolds in terms of local charts and coordinates ...
Legendrian rational unknots in lens spaces
[OWP-2013-06] (Mathematisches Forschungsinstitut Oberwolfach, 2013-03-14)
We classify Legendrian rational unknots with tight complements in the lens spaces $L(p,1)$ up to coarse equivalence. As an example of the general case, this classification is also worked out for $L(5, 2)$. The knots are ...
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, ...
Low rank differential equations for hamiltonian matrix nearness problems
[OWP-2013-01] (Mathematisches Forschungsinstitut Oberwolfach, 2013-02-08)
For a Hamiltonian matrix with purely imaginary eigenvalues, we aim to determine the nearest Hamiltonian matrix such that so me or all eigenvalues leave the imaginary axis. Conversely, for a Hamiltonian matrix with all ...
Local asymptotics for the area of random walk excursions
[OWP-2013-19] (Mathematisches Forschungsinstitut Oberwolfach, 2013-09-05)
We prove a local limit theorem for the area of the positive exursion of random walks with zero mean and finite variance. Our main result complements previous work of Caravenna and Chaumont, Sohier, as well as ...
Multiple Bernoulli series and volumes of moduli spaces of flat bundles over surfaces
[OWP-2013-04] (Mathematisches Forschungsinstitut Oberwolfach, 2013-03-14)
Using Szenes formula for multiple Bernoulli series, we explain how to compute Witten series associated to classical Lie algebras. Particular instances of these series compute volumes of moduli spaces of flat bundles over ...
Grassmannian connection between three- and four-qubit observables, mermin's contextualities and black holes
[OWP-2013-17] (Mathematisches Forschungsinstitut Oberwolfach, 2013-07-23)
We invoke some ideas from finite geometry to map bijectively 135 heptads of mutually commuting three-qubit observables into 135 symmetric four-qubit ones. After labeling the elements of the former set in terms of a ...