Results for "Markus Nagel"

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Swap-invariant and exchangeable random measuresFeb 24 2016Jul 05 2016In this work we analyze the concept of swap-invariance, which is a weaker variant of exchangeability. A random vector $\xi$ in $\mathbb{R}^n$ is called swap-invariant if $\,{\mathbf E}\,\big| \!\sum_j u_j \xi_j \big|\,$ is invariant under all permutations ... More
Level algebras through Buchsbaum* manifoldsJun 22 2010Stanley-Reisner rings of Buchsbaum* complexes are studied by means of their quotients modulo a linear system of parameters. The socle of these quotients is computed. Extending a recent result by Novik and Swartz for orientable homology manifolds without ... More
Moderate deviations for spectral measures of random matrix ensemblesAug 26 2013In this paper we consider the (weighted) spectral measure $\mu_n$ of a $n\times n$ random matrix, distributed according to a classical Gaussian, Laguerre or Jacobi ensemble, and show a moderate deviation principle for the standardised signed measure $\sqrt{n/a_n}(\mu_n ... More
Triple gauge couplings in polarised e-e+ -> W-W+ and their measurement using optimal observablesSep 19 2002The sensitivity of optimal integrated observables to electroweak triple gauge couplings is investigated for the process e-e+ -> W-W+ -> 4 fermions at future linear colliders. By a suitable reparameterisation of the couplings we achieve that all 28 coupling ... More
Probing triple gauge couplings with transverse beam polarisation in e+e- -> W+W-Jun 25 2003Sep 11 2003The prospects of measuring triple gauge couplings in W pair production at future linear colliders with transverse beam polarisation are studied. We consider CP conserving and CP violating couplings with both real and imaginary parts. The maximum achievable ... More
Glicci simplicial complexesApr 24 2007One of the main open questions in liaison theory is whether every homogeneous Cohen-Macaulay ideal in a polynomial ring is glicci, i.e. if it is in the G-liaison class of a complete intersection. We give an affirmative answer to this question for Stanley-Reisner ... More
FI- and OI-modules with varying coefficientsOct 25 2017Nov 02 2017We introduce FI-algebras over a commutative ring $K$ and the category of FI-modules over an FI-algebra. Such a module may be considered as a family of invariant modules over compatible varying $K$-algebras. FI-modules over $K$ correspond to the well studied ... More
Minimal links and a result of GaetaApr 03 2008If $V$ is an equidimensional codimension $c$ subscheme of an $n$-dimensional projective space, and $V$ is linked to $V'$ by a complete intersection $X$, then we say that $V$ is {\em minimally linked} to $V'$ if $X$ is a codimension $c$ complete intersection ... More
Liaison and Related Topics: Notes from the Torino Workshop/SchoolMay 14 2002These are the expanded and detailed notes of the lectures given by the authors during the school and workshop entitled "Liaison and Related Topics," held at the Politecnico di Torino during the period October 1-5, 2001. In these notes we have attempted ... More
On the capacity functional of excursion sets of Gaussian random fields on $\R^2$Oct 28 2014When a random field $(X_t, \ t\in {\mathbb R}^2)$ is thresholded on a given level $u$, the excursion set is given by its indicator $~1_{[u, \infty)}(X_t)$. The purpose of this work is to study functionals (as established in stochastic geometry) of these ... More
Numerical MacaulificationFeb 10 2012An unpublished example due to Joe Harris from 1983 (or earlier) gave two smooth space curves with the same Hilbert function, but one of the curves was arithmetically Cohen-Macaulay (ACM) and the other was not. Starting with an arbitrary homogeneous ideal ... More
Monomial and toric ideals associated to Ferrers graphsSep 13 2006Each partition $\lambda = (\lambda_1, \lambda_2, ..., \lambda_n)$ determines a so-called Ferrers tableau or, equivalently, a Ferrers bipartite graph. Its edge ideal, dubbed Ferrers ideal, is a squarefree monomial ideal that is generated by quadrics. We ... More
Matrix measures, random moments and Gaussian ensemblesApr 24 2009May 17 2011We consider the moment space $\mathcal{M}_n$ corresponding to $p \times p$ real or complex matrix measures defined on the interval $[0,1]$. The asymptotic properties of the first $k$ components of a uniformly distributed vector $(S_{1,n}, ..., S_{n,n})^* ... More
Segre's Regularity Bound for Fat Point SchemesNov 19 2016Motivated by questions in interpolation theory and on linear systems of rational varieties, one is interested in upper bounds for the Castelnuovo-Mumford regularity of arbitrary subschemes of fat points. An optimal upper bound, named after Segre, was ... More
Gorenstein algebras presented by quadricsJun 14 2011We establish restrictions on the Hilbert function of standard graded Gorenstein algebras with only quadratic relations. Furthermore, we pose some intriguing conjectures and provide evidence for them by proving them in some cases using a number of different ... More
A tour of the Weak and Strong Lefschetz PropertiesSep 26 2011Sep 29 2011An artinian graded algebra, $A$, is said to have the Weak Lefschetz property (WLP) if multiplication by a general linear form has maximal rank in every degree. A vast quantity of work has been done studying and applying this property, touching on numerous ... More
Properties of cut ideals associated to ring graphsJun 03 2008Apr 28 2009A cut ideal of a graph records the relations among the cuts of the graph. These toric ideals have been introduced by Sturmfels and Sullivant who also posed the problem of relating their properties to the combinatorial structure of the graph. We study ... More
The Lefschetz question for ideals generated by powers of linear forms in few variablesMar 21 2017Aug 07 2017The Lefschetz question asks if multiplication by a power of a general linear form, $L$, on a graded algebra has maximal rank (in every degree). We consider a quotient by an ideal that is generated by powers of linear forms. Then the Lefschetz question ... More
Ergodic Description of STIT TessellationsNov 09 2010Let (Y_t: t > 0) be the STIT tessellation process. We show that for all polytopes W with nonempty interior and all a>1, the renormalized random sequence (a^n Y_{a^n}: n integer) induced in W, is a finitary factor of a Bernoulli shift. As a corollary we ... More
A new prediction of wavelength selection in radial viscous fingering involving normal and tangential stressesMar 22 2013We reconsider the radial Saffman-Taylor instability, when a fluid injected from a point source displaces another fluid with a higher viscosity in a Hele-Shaw cell, where the fluids are confined between two neighboring flat plates. The advancing fluid ... More
Algorithms for strongly stable idealsOct 18 2011Dec 02 2011Strongly stable monomial ideals are important in algebraic geometry, commutative algebra, and combinatorics. Prompted, for example, by combinatorial approaches for studying Hilbert schemes and the existence of maximal total Betti numbers among saturated ... More
Data-Free Quantization through Weight Equalization and Bias CorrectionJun 11 2019We introduce a data-free quantization method for deep neural networks that does not require fine-tuning or hyperparameter selection. It achieves near-original model performance on common computer vision architectures and tasks. 8-bit fixed-point quantization ... More
STIT Process and TreesNov 12 2014Nov 13 2014We study several constructions of the STIT tessellation process in a window of $\RR^\ell$ and supply an exact formula for its transition probability.
Criteria for componentwise linearityAug 19 2011Oct 11 2011We establish characteristic-free criteria for the componentwise linearity of graded ideals. As applications, we classify the componentwise linear ideals among the Gorenstein ideals, the standard determinantal ideals, and the ideals generated by the submaximal ... More
Betti numbers of monomial ideals and shifted skew shapesDec 15 2007We present two new problems on lower bounds for resolution Betti numbers of monomial ideals generated in a fixed degree. The first concerns any such ideal and bounds the total Betti numbers, while the second concerns ideals that are quadratic and bihomogeneous ... More
On the smallest singular value of multivariate Vandermonde matrices with clustered nodesJul 16 2019We prove lower bounds for the smallest singular value of rectangular, multivariate Vandermonde matrices with nodes on the complex unit circle. The nodes are ``off the grid'', groups of nodes cluster, and the studied minimal singular value is bounded below ... More
Tetrahedral CurvesJul 16 2004A tetrahedral curve is a space curve whose defining ideal is an intersection of powers of monomial prime ideals of height two. It is supported on a tetrahedral configuration of lines. Schwartau described when certain such curves are ACM, namely he restricted ... More
Reduced arithmetically Gorenstein schemes and simplicial polytopes with maximal Betti numbersMar 28 2001An SI-sequence is a finite sequence of positive integers which is symmetric, unimodal and satisfies a certain growth condition. These are known to correspond precisely to the possible Hilbert functions of Artinian Gorenstein algebras with the Weak Lefschetz ... More
Signed lozenge tilingsJul 06 2015It is well-known that plane partitions, lozenge tilings of a hexagon, perfect matchings on a honeycomb graph, and families of non-intersecting lattice paths in a hexagon are all in bijection. In this work we consider regions that are more general than ... More
Spectral covolatility estimation from noisy observations using local weightsDec 05 2011May 23 2013We propose localized spectral estimators for the quadratic covariation and the spot covolatility of diffusion processes which are observed discretely with additive observation noise. The eligibility of this approach to lead to an appropriate estimation ... More
The homotopy Leray spectral sequenceDec 22 2018May 09 2019In this work, we build a spectral sequence in motivic homotopy that is analogous to both the Serre spectral sequence in algebraic topology and the Leray spectral sequence in algebraic geometry. Here, we focus on laying the foundations necessary to build ... More
The Multiplicity Conjecture in low codimensionsOct 22 2004We establish the multiplicity conjecture of Herzog, Huneke, and Srinivasan about the multiplicity of graded Cohen-Macaulay algebras over a field, for codimension two algebras and for Gorenstein algebras of codimension three. In fact, we prove stronger ... More
Buchsbaum-Rim sheaves and their multiple sectionsAug 26 1997This paper begins by introducing and characterizing Buchsbaum-Rim sheaves on $Z = \Proj R$ where $R$ is a graded Gorenstein K-algebra. They are reflexive sheaves arising as the sheafification of kernels of sufficiently general maps between free R-modules. ... More
Exploring the Physical Layer Frontiers of Cellular Uplink - The Vienna LTE-A SimulatorSep 08 2015Communication systems in practice are subject to many technical/technological constraints and restrictions. MIMO processing in current wireless communications, as an example, mostly employs codebook based pre-coding to save computational complexity at ... More
On complete intersections in varieties with finite-dimensional motiveSep 29 2017Let $X$ be a complete intersection inside a variety $M$ with finite dimensional motive and for which the Lefschetz-type conjecture $B(M)$ holds. We show how conditions on the niveau filtration on the homology of $X$ influence directly the niveau on the ... More
Einstein relation and steady states for the random conductance modelDec 07 2015We consider random walk among iid, uniformly elliptic conductances on $\mathbb Z^d$, and prove the Einstein relation (see Theorem 1). It says that the derivative of the velocity of a biased walk as a function of the bias equals the diffusivity in equilibrium. ... More
Bounds for the Castelnuovo-Mumford regularity of modulesSep 01 2006We establish bounds for the Castelnuovo-Mumford regularity of a finitely generated graded module and its symmetric powers in terms of the degrees of the generators of the module and the degrees of their relations. We extend to modules (and improve) the ... More
An improved Multiplicity Conjecture for codimension three Gorenstein algebrasApr 22 2006Jan 09 2007The Multiplicity Conjecture is a deep problem relating the multiplicity (or degree) of a Cohen-Macaulay standard graded algebra with certain extremal graded Betti numbers in its minimal free resolution. In the case of level algebras of codimension three, ... More
A characterization of Gorenstein Hilbert functions in codimension four with small initial degreeMar 29 2007Jul 13 2007The main goal of this paper is to characterize the Hilbert functions of all (artinian) codimension 4 Gorenstein algebras that have at least two independent relations of degree four. This includes all codimension 4 Gorenstein algebras whose initial relation ... More
The speed of biased random walk among random conductancesApr 28 2017We consider biased random walk among iid, uniformly elliptic conductances on $\mathbb{Z}^d$, and investigate the monotonicity of the velocity as a function of the bias. It is not hard to see that if the bias is large enough, the velocity is increasing ... More
The Weak Lefschetz property for quotients by Quadratic MonomialsJun 15 2017In [MMR], Micha\l{}ek--Mir\'o-Roig give a beautiful geometric characterization of Artinian quotients by ideals generated by quadratic or cubic monomials, such that the multiplication map by a general linear form fails to be injective in the first nontrivial ... More
Schemes supported on the singular locus of a hyperplane arrangement in $\mathbb P^n$Aug 11 2019We introduce the use of liaison addition to the study of hyperplane arrangements. For an arrangement, $\mathcal A$, of hyperplanes in $\mathbb P^n$, $\mathcal A$ is free if $R/J$ is Cohen-Macaulay, where $J$ is the Jacobian ideal of $\mathcal A$. Terao's ... More
Liaison addition and the structure of a Gorenstein liaison classNov 30 2006We study the concept of liaison addition for codimension two subschemes of an arithmetically Gorenstein projective scheme. We show how it relates to liaison and biliaison classes of subschemes and use it to investigate the structure of Gorenstein liaison ... More
Extensions of the Multiplicity ConjectureMay 11 2005The Multiplicity conjecture of Herzog, Huneke, and Srinivasan states an upper bound for the multiplicity of any graded $k$-algebra as well as a lower bound for Cohen-Macaulay algebras. In this note we extend this conjecture in several directions. We discuss ... More
An upper limit to photons from first data taken by the Pierre Auger ObservatoryJan 03 2007Many models for ultra-high energy cosmic rays postulate exotic scenarios to explain the sources or the nature of these particles. A characteristic feature of these models is the prediction of a significant flux of photons at ultra-high energy. The Pierre ... More
Yet another criterion for global existence in the 3D relativistic Vlasov-Maxwell systemJun 05 2014We prove that solutions of the 3D relativistic Vlasov-Maxwell system can be extended, as long as the quantity $\sigma_{-1}(t, x) = \max_{|\omega|=1} \,\int_{R^3} \frac{dp}{\sqrt{1+p^2}}\, \frac{1}{(1+v\cdot\omega)}\, f(t, x, p)$ is bounded in $L^2_x$. ... More
A simple bijection between permutation matrices and descending plane partitions without special partsMay 04 2016Sep 19 2016We present a simple bijection between permutation matrices and descending plane partitions without special parts. This bijection involves the inversion words of permutations and the (well-known) representation of descending plane partitions as families ... More
Multiple hard scattering and parton correlations in the protonNov 04 2014This proceedings contribution gives a brief introduction to the theoretical description of double parton scattering and discusses several open problems.
Nonvanishing and Central Critical Values of Twisted $L$-functions of Cusp Forms on AverageFeb 09 2015Let $f$ be a holomorphic cusp form of integral weight $k \geq 3$ for $\Gamma_{0}(N)$ with nebentypus character $\psi$. Generalising work of Kohnen and Raghuram we construct a kernel function for the $L$-function $L(f,\chi,s)$ of $f$ twisted by a primitive ... More
Alexander-Beck modules detect the unknotOct 26 2016We introduce the Alexander-Beck module of a knot as a canonical refinement of the classical Alexander module, and we prove that this new invariant is an unknot-detector.
Persistent Contextual Values as Inter-Process LayersOct 14 2016Mobile applications today often fail to be context aware when they also need to be customizable and efficient at run-time. Context-oriented programming allows programmers to develop applications that are more context aware. Its central construct, the ... More
Multiphonon emission model of spin-dependent exciton formation in organic semiconductorsOct 18 2004The maximum efficiency in organic light-emitting diodes (OLEDs) depends on the ratio, $r=k_S/k_T$, where $k_S$ ($k_T$) is the singlet (triplet) exciton formation rate. Several recent experiments found that r increases with increasing oligomer length from ... More
Charge fluctuations and dephasing in coulomb coupled conductorsNov 12 1999It is shown that the dephasing rate in Coulomb coupled mesoscopic structures is determined by charge relaxation resistances. The charge relaxation resistance together with the capacitance determines the RC-time of the mesoscopic structure and at small ... More
Decoherence from Vacuum FluctuationsMay 28 2001Vacuum fluctuations are a source of irreversibility and decoherence. We investigate the persistent current and its fluctuations in a ring with an in-line quantum dot with an Aharonov-Bohm flux through the hole of the ring. The Coulomb blockade leads to ... More
Variational Inequalities and Improved Convergence Rates for Tikhonov Regularisation on Banach SpacesJul 13 2011In this paper we derive higher order convergence rates in terms of the Bregman distance for Tikhonov like convex regularisation for linear operator equations on Banach spaces. The approach is based on the idea of variational inequalities, which are, however, ... More
Orthogonal projectors onto spaces of periodic splinesAug 24 2016The main result of this paper is a proof that for any integrable function $f$ on the torus, any sequence of its orthogonal projections $(\widetilde{P}_n f)$ onto periodic spline spaces with arbitrary knots $\widetilde{\Delta}_n$ and arbitrary polynomial ... More
The Complexity of Linear Tensor Product Problems in (Anti-) Symmetric Hilbert SpacesOct 31 2011Aug 14 2012We study linear problems defined on tensor products of Hilbert spaces with an additional (anti-) symmetry property. We construct a linear algorithm that uses finitely many continuous linear functionals and show an explicit formula for its worst case error ... More
Constraints on the Geometry of the VHE Emission in LS 5039 from Photon-Photon DeabsorptionSep 05 2006Nov 20 2006A detailed parameter study of the gamma-gamma absorption effects in LS 5039 is presented. For a range of plausible locations of the VHE gamma-ray emission region and the allowable range of viewing angles, the de-absorbed, intrinsic VHE gamma-ray spectra ... More
Charmless 2- and 3-body B decays and the angle alpha (phi2)Oct 20 2004We present preliminary measurements of branching fractions and CP-asymmetry parameters in two- and three-body charmless hadronic B decays. The available data sample consists of 227 million Upsilon(4S) B decays collected with the BABAR detector at the ... More
On the existence of (H,A)-stable sheaves on K3 or abelian surfacesFeb 20 2013We give an existence result on (H,A)-stable sheaves on a K3 or abelian surface X with primitive triple of invariants (rank,first Chern class,Euler characteristics) in the integral cohomology lattice. Such a result yields the existence of singular projective ... More
Round Table Summary: Stellar interferometry as a tool to investigate atmospheres and to compare observations with modelsApr 02 2003Long-baseline interferometry at optical and near-infrared wavelengths is an emerging technology which is quickly becoming a useful tool to investigate stellar atmospheres and to compare observations with models. Stellar atmosphere models have so far mainly ... More
Tate duality and transfer in Hochschild cohomologyNov 26 2012We show that dualising transfer maps in Hochschild cohomology of symmetric algebras commutes with Tate duality. This extends a well-known result in group cohomology.
Cohomology of quiver moduli, functional equations, and integrality of Donaldson-Thomas type invariantsMar 02 2009A system of functional equations relating the Euler characteristics of moduli spaces of stable representations of quivers and the Euler characteristics of (Hilbert scheme-type) framed versions of quiver moduli is derived. This is applied to wall-crossing ... More
Counting rational points of quiver moduliMay 18 2005It is shown that rational points over finite fields of moduli spaces of stable quiver representations are counted by polynomials with integer coefficients. These polynomials are constructed recursively using an identity in the Hall algebra of a quiver. ... More
Cohomology of non-commutative Hilbert schemesJun 11 2003Sep 04 2003Non-commutative Hilbert schemes, introduced by M. V. Nori, parametrize left ideals of finite codimension in free algebras. More generally, parameter spaces of finite codimensional submodules of free modules over free algebras are considered. Cell decompositions ... More
The monoid of families of quiver representationsMay 15 2001A monoid structure on families of representations of a quiver is introduced by taking extensions of representations in families, i.e. subvarieties of the varieties of representations. The study of this monoid leads to interesting interactions between ... More
A Systematic Search for Trojan Planets in the Kepler dataJul 26 2013Trojans are circumstellar bodies that reside in characteristic 1:1 orbital resonances with planets. While all the trojans in our Solar System are small (< ~100 km), stable planet-size trojans may exist in extrasolar planetary systems, and the Kepler telescope ... More
From form factors to generalized parton distributionsJun 25 2013I present an extraction of generalized parton distributions from selected data on the electromagnetic nucleon form factors. The extracted distributions can in particular be used to quantify the contribution to the proton spin from the total angular momentum ... More
A note on hook length formulas for treesApr 12 2010In this short note we discuss recent results on hook length formulas of trees unifying some earlier results, and explain hook length formulas naturally associated to families of increasingly labelled trees.
A note on naturally embedded ternary treesFeb 16 2009Mar 09 2009In this note we consider ternary trees naturally embedded in the plane in a deterministic way such that the root has position zero, or in other words label zero, and the children of a node with position $j$ have positions $j-1$, $j$, and $j+1$, for all ... More
Gas in Shearing Density WavesDec 04 1997We examine the development of a transient spiral arm in a disk galaxy made up of both gas and stars. To this end we have performed numerical simulations in a shearing sheet (basically a rectangular patch of a disc) that contains gas in the form of clouds ... More
Homology and the stability problem in the Thompson group familyNov 18 2014Mar 24 2015We prove that Thompson's group V is acyclic. The strategy of our proof stems from the context of homological stability and stable homology. We first use algebraic K-theory methods to compute the stable homology for automorphism groups of algebraic theories ... More
Dynamical quantum phase transitions: scaling and universalityMay 10 2015Oct 05 2015Dynamical quantum phase transitions (DQPTs) at critical times appear as non-analyticities during nonequilibrium quantum real-time evolution. Although there is evidence for a close relationship between DQPTs and equilibrium phase transitions, a major challenge ... More
Knapsack in hyperbolic groupsJul 18 2018Recently knapsack problems have been generalized from the integers to arbitrary finitely generated groups. The knapsack problem for a finitely generated group $G$ is the following decision problem: given a tuple $(g, g_1, \ldots, g_k)$ of elements of ... More
2:3:4-Harmony within the TritaveSep 01 2017Aug 01 2018In the Pythagorean tuning system, the fifth is used to generate a scale of 12 notes per octave. In this paper, we use the octave to generate a scale of 19 notes per tritave; one can play this scale on a traditional piano. In this system, the octave becomes ... More
The Intertropical Convergence ZoneAug 30 2017This activity has been developed as a resource for the "EU Space Awareness" educational programme. As part of the suite "Our Fragile Planet" together with the "Climate Box" it addresses aspects of weather phenomena, the Earth's climate and climate change ... More
A View From AboveSep 04 2017This activity has been developed as a resource for the "EU Space Awareness" educational programme. As part of the suite "Our Fragile Planet" together with the "Climate Box" it addresses aspects of weather phenomena, the Earth's climate and climate change ... More
Asymptotics of the average height of 2--watermelons with a wallJul 06 2006Sep 04 2006We generalize the classical work of de Bruijn, Knuth and Rice (giving the asymptotics of the average height of Dyck paths of length $n$) to the case of $p$--watermelons with a wall (i.e., to a certain family of $p$ nonintersecting Dyck paths; simple Dyck ... More
Nonintersecting lattice paths on the cylinderNov 19 2003Feb 18 2004We show how a formula concerning ``vicious walkers'' (which basically are nonintersecting lattice paths) on the cylinder given by P.J. Forrester can be proved and generalized by using the Lindstr\"om--Gessel--Viennot method, after having things set up ... More
First-passage dynamics of linear stochastic interface models: numerical simulations and entropic repulsion effectAug 11 2017Mar 25 2018A fluctuating interfacial profile in one dimension is studied via Langevin simulations of the Edwards-Wilkinson equation with non-conserved noise and the Mullins-Herring equation with conserved noise. The profile is subject to either periodic or Dirichlet ... More
Analysis of mesoscale forecasts using ensemble methodsOct 24 2016Mesoscale forecasts are now routinely performed as elements of operational forecasts and their outputs do appear convincing. However, despite their realistic appearance at times the comparison to observations is less favorable. At the grid scale these ... More
Large Deviations and Phase Transition for Random Walks in Random Nonnegative PotentialsSep 27 2006We establish large deviation principles and phase transition results for both quenched and annealed settings of nearest-neighbor random walks with constant drift in random nonnegative potentials on $\mathbb Z^d$. We complement the analysis of \cite{Zer}, ... More
Magnetoresistance and localization in bosonic insulatorsSep 01 2011Jul 12 2013We study the strong localization of hard core bosons. Using a locator expansion we find that in the insulator, unlike for typical fermion problems, nearly all low-energy scattering paths come with positive amplitudes and hence interfere constructively. ... More
On the Quantum Kolmogorov Complexity of Classical StringsJul 19 2007Jun 09 2009We show that classical and quantum Kolmogorov complexity of binary strings agree up to an additive constant. Both complexities are defined as the minimal length of any (classical resp. quantum) computer program that outputs the corresponding string. It ... More
Temiar Reduplication in One-Level Prosodic MorphologyAug 18 2000Temiar reduplication is a difficult piece of prosodic morphology. This paper presents the first computational analysis of Temiar reduplication, using the novel finite-state approach of One-Level Prosodic Morphology originally developed by Walther (1999b, ... More
Finite-State Reduplication in One-Level Prosodic MorphologyMay 22 2000Reduplication, a central instance of prosodic morphology, is particularly challenging for state-of-the-art computational morphology, since it involves copying of some part of a phonological string. In this paper I advocate a finite-state method that combines ... More
On a Family of Random Noble Means SubstitutionsDec 18 2013In 1989, Godreche and Luck introduced the concept of local mixtures of primitive substitution rules along the example of the well-known Fibonacci substitution and foreshadowed heuristic results on the topological entropy and the spectral type of the diffraction ... More
Isometric Group Actions and the Cohomology of Flat Fiber BundlesMay 04 2011Using methods originating in the theory of intersection spaces, specifically a de Rham type description of the real cohomology of these spaces by a complex of global differential forms, we show that the Leray-Serre spectral sequence with real coefficients ... More
A criterion for membership in archimedean semiringsSep 23 2004We prove an extension of the classical Real Representation Theorem (going back to Krivine, Stone, Kadison, Dubois and Becker and often called Kadison-Dubois Theorem). It is a criterion for membership in subsemirings (sometimes called preprimes) of a commutative ... More
Systems of submodules and a remark by M.C.R. ButlerJul 27 2005Sep 13 2006Fix a poset $P$ and a natural number $n$. For various commutative local rings $\Lambda$, each of Loewy length $n$, consider the category $\textrm{sub}_\Lambda P$ of $\Lambda$-linear submodule representations of $P$. We give a criterion for when the underlying ... More
Iterated rings of bounded elements: ErratumOct 31 2005We close a gap appearing at the same time in the author's thesis "Iterated rings of bounded elements and generalizations of Schm\"udgen's theorem" [1] and in the author's article "Iterated rings of bounded elements and generalizations of Schm\"udgen's ... More
Deep Generative Networks For Sequence PredictionApr 18 2018This thesis investigates unsupervised time series representation learning for sequence prediction problems, i.e. generating nice-looking input samples given a previous history, for high dimensional input sequences by decoupling the static input representation ... More
Long-range self-avoiding walk converges to alpha-stable processesSep 25 2008Nov 20 2009We consider a long-range version of self-avoiding walk in dimension $d > 2(\alpha \wedge 2)$, where $d$ denotes dimension and $\alpha$ the power-law decay exponent of the coupling function. Under appropriate scaling we prove convergence to Brownian motion ... More
Ornstein-Uhlenbeck processes driven by cylindrical Lévy processesDec 16 2012May 28 2014In this article we introduce a theory of integration for deterministic, operator-valued integrands with respect to cylindrical L\'evy processes in separable Banach spaces. Here, a cylindrical L\'evy process is understood in the classical framework of ... More
Asymptotic equivalence and sufficiency for volatility estimation under microstructure noiseJan 18 2010The basic model for high-frequency data in finance is considered, where an efficient price process is observed under microstructure noise. It is shown that this nonparametric model is in Le Cam's sense asymptotically equivalent to a Gaussian shift experiment ... More
A babystep-giantstep method for faster deterministic integer factorizationAug 31 2016Jul 06 2017In 1977, Strassen presented a deterministic and rigorous algorithm for solving the problem of computing the prime factorization of natural numbers $N$. His method is based on fast polynomial arithmetic techniques and runs in time $\widetilde{O}(N^{1/4})$, ... More
Another viewpoint on J-spacesDec 06 2010Dec 10 2010We give an interpretation of J-spaces in terms of symmetric spectra in symmetric sequences. As application we show how one can define graded endomorphism objects in a general situation. As example we discuss the motivic bigraded endomorphisms of a motivic ... More
Poisson automorphisms and quiver moduliApr 20 2008Jun 05 2009A factorization formula for certain automorphisms of a Poisson algebra associated to a quiver is proved, which involves framed versions of moduli spaces of quiver representations. This factorization formula is related to wall-crossing formulas for Donaldson-Thomas ... More
Moduli for Equivariant Vector Bundles of Rank Two on Smooth Toric SurfacesMay 30 2002We give a complete classification of equivariant vector bundles of rank two over smooth complete toric surfaces and construct moduli spaces of such bundles. This note is a direct continuation of an earlier note where we developed a general description ... More
A lifting functor for toric sheavesOct 03 2011Aug 17 2012For a variety X which admits a Cox ring we introduce a functor from the category of quasi-coherent sheaves on $X$ to the category of graded modules over the homogeneous coordinate ring of $X$. We show that this functor is right-adjoint to the sheafification ... More