Now showing items 4-23 of 340

• #### Abstract Bivariant Cuntz Semigroups ﻿

[OWP-2017-04] (Mathematisches Forschungsinstitut Oberwolfach, 2017-02-13)
We show that abstract Cuntz semigroups form a closed symmetric monoidal category. Thus, given Cuntz semigroups $S$ and $T$, there is another Cuntz semigroup $((S,T))$ playing the role of morphisms from $S$ to $T$. Applied ...
• #### Abundance of 3-Planes on Real Projective Hypersurfaces ﻿

[OWP-2014-14] (Mathematisches Forschungsinstitut Oberwolfach, 2014-11-11)
We show that a generic real projective n-dimensional hypersurface of odd degree $d$, such that $4(n-2)=\binom{d+3}{3}$, contains "many" real 3-planes, namely, in the logarithmic scale their number has the same rate of ...
• #### Affine Space Fibrations ﻿

[OWP-2018-19] (Mathematisches Forschungsinstitut Oberwolfach, 2018-09-05)
We discuss various aspects of affine space fibrations. Our interest will be focused in the singular fibers, the generic fiber and the propagation of properties of a given smooth special fiber to nearby fibers.
• #### Alexander r-Tuples and Bier Complexes ﻿

[OWP-2016-17] (Mathematisches Forschungsinstitut Oberwolfach, 2016-10)
We introduce and study Alexander $r$-Tuples $\mathcal{K} = \langle K_i \rangle ^r_{i=1}$ of simplicial complexes, as a common generalization of pairs of Alexander dual complexes (Alexander 2-tuples) and r-unavoidable ...
• #### The algebra of differential operators for a Gegenbauer weight matrix ﻿

[OWP-2015-07] (Mathematisches Forschungsinstitut Oberwolfach, 2015-07-29)
In this work we study in detail the algebra of differential operators $\mathcal{D}(W)$ associated with a Gegenbauer matrix weight. We prove that two second order operators generate the algebra, indeed $\mathcal{D}(W)$ is ...
• #### The algebraic combinatorial approach for low-rank matrix completion ﻿

[OWP-2013-05] (Mathematisches Forschungsinstitut Oberwolfach, 2013-03-14)
We propose an algebraic combinatorial framework for the problem of completing partially observed low-rank matrices. We show that the intrinsic properties of the problem, including which entries can be reconstructed, and ...
• #### Algebraic geometric comparison of probability distributions ﻿

[OWP-2011-30] (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-27)
We propose a novel algebraic framework for treating probability distributions represented by their cumulants such as the mean and covariance matrix. As an example, we consider the unsupervised learning problem of finding ...
• #### Algebraic Matroids with Graph Symmetry ﻿

[OWP-2014-02] (Mathematisches Forschungsinstitut Oberwolfach, 2014)
This paper studies the properties of two kinds of matroids: (a) algebraic matroids and (b) finite and infinite matroids whose ground set have some canonical symmetry, for example row and column symmetry and transposition ...
• #### Alternative iterative methods for nonexpansive mappings, rates of convergence and applications ﻿

[OWP-2009-19] (Mathematisches Forschungsinstitut Oberwolfach, 2009)
Alternative iterative methods for a nonexpansive mapping in a Banach space are proposed and proved to be convergent to a common solution to a fixed point problem and a variational inequality. We give rates of asymptotic ...
• #### Analysis and Simulation of a New Multi-Component Two-Phase Flow Model with Phase Transitions and Chemical Reactions ﻿

[OWP-2017-08] (Mathematisches Forschungsinstitut Oberwolfach, 2017-03-15)
A class-II model for multi-component mixtures recently introduced in D. Bothe, W. Dreyer, Continuum thermodynamics of chemically reacting fluid mixtures, Acta Mech., 226 (2015), 1757–1805 is investigated for simple mixtures. ...
• #### Analytic Structure in Fibers ﻿

[OWP-2016-13] (Mathematisches Forschungsinstitut Oberwolfach, 2016-08-17)
Let $B_X$ be the open unit ball of a complex Banach space $X$, and let $\mathcal{H}^\infty(B_X)$ and $\mathcal{A}_u(B_X)$ be, respectively, the algebra of bounded holomorphic functions on $B_X$ and the subalgebra of uniformly ...
• #### Analytic Varieties with Finite Volume Amoebas are Algebraic ﻿

[OWP-2011-33] (Mathematisches Forschungsinstitut Oberwolfach, 2011)
In this paper, we study the amoeba volume of a given $k$-dimensional generic analytic variety $V$ of the complex algebraic torus $(C^*)^n$. When $n>=2k$, we show that $V$ is algebraic if and only if the volume of its amoeba ...
• #### Applications of BV Type Spaces ﻿

[OWP-2019-04] (Mathematisches Forschungsinstitut Oberwolfach, 2019-02-13)
• #### Approximation of discrete functions and size of spectrum ﻿

[OWP-2009-17] (Mathematisches Forschungsinstitut Oberwolfach, 2009-03-11)
Let $\Lambda \subset \mathbb{R}$ be a uniformly discrete sequence and $S \subset \mathbb{R}$ a compact set. We prove that if there exists a bounded sequence of functions in Paley-Wiener space $PW_s$, which approximates ...
• #### Asymptotic behavior of the eigenvalues and eigenfunctions to a spectral problem in thick cascade junction with concentrated masses ﻿

[OWP-2011-12] (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-14)
The asymptotic behavior (as $\varepsilon \to 0$) of eigenvalues and eigenfunctions of a boundaryvalue problem for the Laplace operator in a thick cascade junction with concentrated masses is investigated. This cascade ...
• #### Averages of Shifted Convolutions of d3(n) ﻿

[OWP-2011-11] (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-13)
We investigate the first and second moments of shifted convolutions of the generalised divisor function $d_3(n)$.
• #### The Becker-Gottlieb Transfer: a Geometric Description ﻿

[OWP-2019-13] (Mathematisches Forschungsinstitut Oberwolfach, 2019-05-14)
In this note, we examine geometric aspects of the Becker-Gottlieb transfer in terms of the Umkehr and index maps, and rework some classic index theorems, using the cohomological formulae of the Becker-Gottlieb transfer. ...
• #### The Berry-Keating Operator on a Lattice ﻿

[OWP-2016-23] (Mathematisches Forschungsinstitut Oberwolfach, 2016-11-17)
We construct and study a version of the Berry-Keating operator with a built-in truncation of the phase space, which we choose to be a two-dimensional torus. The operator is a Weyl quantisation of the classical Hamiltonian ...
• #### Boundary Representations of Operator Spaces, and Compact Rectangular Matrix Convex Sets ﻿

[OWP-2016-24] (Mathematisches Forschungsinstitut Oberwolfach, 2016-12-13)
We initiate the study of matrix convexity for operator spaces. We define the notion of compact rectangular matrix convex set, and prove the natural analogs of the Krein-Milman and the bipolar theorems in this context. We ...
• #### Braid equivalences and the L-moves ﻿

[OWP-2011-20] (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-19)
In this survey paper we present the L-moves between braids and how they can adapt and serve for establishing and proving braid equivalence theorems for various diagrammatic settings, such as for classical knots, for knots ...