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The Nagata automorphism is shifted linearizable
[OWP200809] (Mathematisches Forschungsinstitut Oberwolfach, 20080313)A polynomial automorphism $F$ is called shifted linearizable if there exists a linear map $L$ such that $LF$ is linearizable. We prove that the Nagata automorphism $N:= (XY\DeltaZ\Delta^2,Y+Z\Delta,Z)$ where $\Delta=XZ+Y^2$ ... 
Near critical density irregular sampling in bernstein spaces
[OWP201316] (Mathematisches Forschungsinstitut Oberwolfach, 20130723)We obtain sharp estimates for the sampling constants in Bernstein spaces when the density of the sampling set is near the critical value. 
A nested family of ktotal effective rewards for positional games
[OWP201521] (Mathematisches Forschungsinstitut Oberwolfach, 2015)We consider Gillette's twoperson zerosum stochastic games with perfect information. For each $k \in \mathbb{Z}_+$ we introduce an effective reward function, called $k$total. For $k = 0$ and $1$ this function is known ... 
A new counting function for the zeros of holomorphic curves
[OWP200925] (Mathematisches Forschungsinstitut Oberwolfach, 20090318)Let $f_1,..., f_p$ be entire functions that do not all vanish at any point, so that $(f_1,..., f_p)$ is a holomorphic curve in $\mathbb{CP}^{p1}$. We introduce a new and more careful notion of counting the order of the ... 
New representations of matroids and generalizations
[OWP201118] (Mathematisches Forschungsinstitut Oberwolfach, 2011)We extend the notion of matroid representations by matrices over fields by considering new representations of matroids by matrices over finite semirings, more precisely over the boolean and the superboolean semirings. This ... 
News on quadratic polynomials
[SNAP2017002EN] (Mathematisches Forschungsinstitut Oberwolfach, 20170718)Many problems in mathematics have remained unsolved because of missing links between mathematical disciplines, such as algebra, geometry, analysis, or number theory. Here we introduce a recently discovered result concerning ... 
NonExtendability of Holomorphic Functions with Bounded or Continuously Extendable Derivatives
[OWP201730] (Mathematisches Forschungsinstitut Oberwolfach, 20171021)We consider the spaces $H_{F}^{\infty}(\Omega)$ and $\mathcal{A}_{F}(\Omega)$ containing all holomorphic functions $f$ on an open set $\Omega \subseteq \mathbb{C}$, such that all derivatives $f^{(l)}$, $l\in F \subseteq ... 
Nonintegrated defect relation for meromorphic maps of complete Kähler manifolds into a projective variety intersecting hypersurfaces
[OWP201019] (Mathematisches Forschungsinstitut Oberwolfach, 2010)In 1985, Fujimoto established a nonintegrated defect relation for meromorphic maps of complete Kähler manifolds into the complex projective space intersecting hyperplanes in general position. In this paper, we generalize ... 
NonStandard Behavior of Density Estimators for Sums of Squared Observations
[OWP200807] (Mathematisches Forschungsinstitut Oberwolfach, 20080311)It has been shown recently that, under an appropriate integrability condition, densities of functions of independent and identically distributed random variables can be estimated at the parametric rate by a local Ustatistic, ... 
Nonstationary multivariate subdivision: joint spectral radius and asymptotic similarity
[OWP201320] (Mathematisches Forschungsinstitut Oberwolfach, 20131029)In this paper we study scalar multivariate nonstationary subdivision schemes with a general integer dilation matrix. We present a new numerically efficient method for checking convergence and Hölder ... 
Noncommutative Marked Surfaces
[OWP201516] (Mathematisches Forschungsinstitut Oberwolfach, 20151118)The aim of the paper is to attach a noncommutative clusterlike structure to each marked surface $\Sigma$. This is a noncommutative algebra $\mathcal{A}_\Sigma$ generated by “noncommutative geodesics” between marked points ... 
Noncommutative topological entropy of endomorphismus of Cuntz Algebras
[OWP200812] (Mathematisches Forschungsinstitut Oberwolfach, 20080316)Noncommutative topological entropy estimates are obtained for ‘finite range’ endomorphisms of Cuntz algebras,generalising known results for the canonical shift endomorphisms. Exact values are computed for a class of ... 
Noncompact harmonic manifolds
[OWP201308] (Mathematisches Forschungsinstitut Oberwolfach, 20130410)The Lichnerowicz conjecture asserts that all harmonic manifolds are either flat or locally symmetric spaces of rank 1. This conjecture has been proved by Z.I. Szab ́o [Sz] for harmonic manifolds with compact universal ... 
Nonlinear matroid optimization and experimental design
[OWP200706] (Mathematisches Forschungsinstitut Oberwolfach, 20070324)We study the problem of optimizing nonlinear objective functions over matroids presented by oracles or explicitly. Such functions can be interpreted as the balancing of multicriteria optimization. We provide a combinatorial ... 
Nonlinear methods in Riemannian and Kählerian geometry
(Birkhäuser Basel, 1986)In this book, I present an expanded version of the contents of my lectures at a Seminar of the DMV (Deutsche Mathematiker Vereinigung) in Diisseldorf, June, 1986. The title "Nonlinear methods in complex geometry" already ... 
Nonlinear MultiParameter Eigenvalue Problems for Systems of Nonlinear Ordinary Differential Equations Arising in Electromagnetics
[OWP201415] (Mathematisches Forschungsinstitut Oberwolfach, 20141220)We investigate a generalization of oneparameter eigenvalue problems arising in the theory of nonlinear waveguides to a more general nonlinear multiparameter eigenvalue problem for a nonlinear operator. Using an integral ... 
Nonlinear Optimization for Matroid Intersection and Extensions
[OWP200814] (Mathematisches Forschungsinstitut Oberwolfach, 20080317)We address optimization of nonlinear functions of the form $f(W_x)$ , where $f : \mathbb{R}^d \to \mathbb{R}$ is a nonlinear function, $W$ is a $d \times n$ matrix, and feasible $x$ are in some large finite set $\mathcal{F}$ ... 
Nonlinear optimization over a Weighted Independence System
[OWP200810] (Mathematisches Forschungsinstitut Oberwolfach, 20080314)We consider the problem of optimizing a nonlinear objective function over a weighted independence system presented by a linearoptimization oracle. We provide a polynomialtime algorithm that determines an rbest solution ... 
A note on delta hedging in markets with jumps
[OWP201123] (Mathematisches Forschungsinstitut Oberwolfach, 20110521)Modelling stock prices via jump processes is common in financial markets. In practice, to hedge a contingent claim one typically uses the socalled deltahedging strategy. This strategy stems from the Black–Merton–Scholes ... 
A note on k[z]Automorphisms in Two Variables
[OWP200817] (Mathematisches Forschungsinstitut Oberwolfach, 2008)We prove that for a polynomial $f \in k[x, y, z]$ equivalent are: (1)$f$ is a $k[z]$coordinate of $k[z][x,y]$, and (2) $k[x, y, z]/(f)\cong k^[2]$ and $f(x,y,a)$ is a coordinate in $k[x,y]$ for some $a \in k$. This solves ...