• Abstract Bivariant Cuntz Semigroups 

      [OWP-2017-04] Antoine, Ramon; Perera, Francesc; Thiel, Hannes (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 ...
    • 1716 - Algebraic Statistics 

      [OWR-2017-20] (2017) - (16 Apr - 22 Apr 2017)
      Algebraic Statistics is concerned with the interplay of techniques from commutative algebra, combinatorics, (real) algebraic geometry, and related fields with problems arising in statistics and data science. This workshop ...
    • 1813 - Applied Harmonic Analysis and Data Processing 

      [OWR-2018-14] (2018) - (25 Mar - 31 Mar 2018)
      Massive data sets have their own architecture. Each data source has an inherent structure, which we should attempt to detect in order to utilize it for applications, such as denoising, clustering, anomaly detection, knowledge ...
    • 1534 - Applied Harmonic Analysis and Sparse Approximation 

      [OWR-2015-38] (2015) - (16 Aug - 22 Aug 2015)
      Efficiently analyzing functions, in particular multivariate functions, is a key problem in applied mathematics. The area of applied harmonic analysis has a significant impact on this problem by providing methodologies both ...
    • 1224 - Applied Harmonic Analysis and Sparse Approximation 

      [OWR-2012-29] (2012) - (10 Jun - 16 Jun 2012)
      Applied harmonic analysis and sparse approximation are highly active research areas with a lot of recent exciting developments. Their methods have become crucial for a wide range of applications in technology and science, ...
    • 1514 - Arbeitsgemeinschaft: The Kadison-Singer Conjecture 

      [OWR-2015-17] (2015) - (29 Mar - 04 Apr 2015)
      The solution to the Kadison–Singer conjecture used techniques that intersect a number of areas of mathematics. The goal of this Arbeitsgemeinschaft was to bring together people from each of these fields to support interactions ...
    • 1744b - Copositivity and Complete Positivity 

      [OWR-2017-52] (2017) - (29 Oct - 04 Nov 2017)
      A real matrix $A$ is called copositive if $x^TAx \ge 0$ holds for all $x \in \mathbb R^n_+$. A matrix $A$ is called completely positive if it can be factorized as $A = BB^T$ , where $B$ is an entrywise nonnegative matrix. ...
    • A Deformed Quon Algebra 

      [OWP-2018-11] Randriamaro, Hery (Mathematisches Forschungsinstitut Oberwolfach, 2018-06-25)
      The quon algebra is an approach to particle statistics in order to provide a theory in which the Pauli exclusion principle and Bose statistics are violated by a small amount. The quons are particles whose annihilation and ...
    • 0813 - Disordered Systems: Random Schrödinger Operators and Random Matrices 

      [OWR-2008-16] (2008) - (23 Mar - 29 Mar 2008)
    • Generalized Vector Cross Products and Killing Forms on Negatively Curved Manifolds 

      [OWP-2018-17] Barberis, María Laura; Moroianu, Andrei; Semmelmann, Uwe (Mathematisches Forschungsinstitut Oberwolfach, 2018-07-17)
      Motivated by the study of Killing forms on compact Riemannian manifolds of negative sectional curvature, we introduce the notion of generalized vector cross products on $\mathbb{R}^n$ and give their classification. Using ...
    • Geometry of Free Loci and Factorization of Noncommutative Polynomials 

      [OWP-2017-23] Helton, J. William; Klep, Igor; Volčič, Jurij; Helton, J. William (Mathematisches Forschungsinstitut Oberwolfach, 2017-10-02)
      The free singularity locus of a noncommutative polynomial f is defined to be the sequence $Z_n(f)=\{X\in M_n^g : \det f(X)=0\}$ of hypersurfaces. The main theorem of this article shows that f is irreducible if and only if ...
    • Infeasibility certificates for linear matrix inequalities 

      [OWP-2011-28] Klep, Igor; Schweighofer, Markus (Mathematisches Forschungsinstitut Oberwolfach, 2011-05-25)
      Farkas' lemma is a fundamental result from linear programming providing linear certi cates for infeasibility of systems of linear inequalities. In semidefinite programming, such linear certificates only exist for strongly ...
    • 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 ...
    • 0651 - Konvexgeometrie 

      [OWR-2006-56] (2006) - (17 Dec - 23 Dec 2006)
      The geometry of convex domains in Euclidean space plays a central role in several branches of mathematics: functional and harmonic analysis, the theory of PDE, linear programming and, increasingly, in the study of other ...
    • 0933 - Linear and Nonlinear Eigenproblems for PDEs 

      [OWR-2009-37] (2009) - (09 Aug - 15 Aug 2009)
      The workshop discussed the numerical solution of linear and nonlinear eigenvalue problems for partial differential equations. It included the theoretical analysis the development of new (adaptive) methods, the iterative ...
    • Low rank differential equations for hamiltonian matrix nearness problems 

      [OWP-2013-01] Guglielmi, Nicola; Kreßner, Daniel; Lubich, Christian (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 ...
    • The Magic Square of Reflections and Rotations 

      [OWP-2018-13] Buchweitz, Ragnar-Olaf; Faber, Eleonore; Ingalls, Colin (Mathematisches Forschungsinstitut Oberwolfach, 2018-07-01)
      We show how Coxeter’s work implies a bijection between complex reflection groups of rank two and real reflection groups in 0(3). We also consider this magic square of reflections and rotations in the framework of Clifford ...
    • 1416a - Mini-Workshop: Mathematical Physics meets Sparse Recovery 

      [OWR-2014-18] (2014) - (13 Apr - 19 Apr 2014)
      In recent years, there have been several fruitful interchanges of methods between the fields of sparse and low-rank recovery on the one hand and quantum information theory on the other hand. One way to understand this ...
    • Non-stationary multivariate subdivision: joint spectral radius and asymptotic similarity 

      [OWP-2013-20] Charina, Maria; Conti, Costanza; Guglielmi, Nicola; Protasov, Vladimir (Mathematisches Forschungsinstitut Oberwolfach, 2013-10-29)
      In this paper we study scalar multivariate non-stationary subdivision schemes with a general integer dilation matrix. We present a new numerically efficient method for checking convergence and Hölder ...