Results for "Fabian Gieseke"

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Learning Selection Masks for Deep Neural NetworksJun 11 2019Data have often to be moved between servers and clients during the inference phase. For instance, modern virtual assistants collect data on mobile devices and the data are sent to remote servers for the analysis. A related scenario is that clients have ... More
Training Big Random Forests with Little ResourcesFeb 18 2018Without access to large compute clusters, building random forests on large datasets is still a challenging problem. This is, in particular, the case if fully-grown trees are desired. We propose a simple yet effective framework that allows to efficiently ... More
Uncertainties of Sudakov form factorsDec 22 2004We study the uncertainties of Sudakov form factors as the basis for parton shower evolution in Monte Carlo event generators. We discuss the particular cases of systematic uncertainties of parton distribution functions and scale uncertainties.
Event Generators - New DevelopmentsOct 22 2002After an introduction to event generators we give an overview of developments in the field of joining matrix elements with parton showers. Starting with matrix element corrections, we also discuss implementations that match LO and NLO matrix elements ... More
NLO corrections to the photon impact factorAug 15 2002We review the program of the calculation of next-to-leading order corrections to the virtual photon impact factor. Following a brief introduction we present some technical aspects for the various contributions. Recently obtained results for transversely ... More
Return of the features. Efficient feature selection and interpretation for photometric redshiftsMar 27 2018May 09 2018The explosion of data in recent years has generated an increasing need for new analysis techniques in order to extract knowledge from massive datasets. Machine learning has proved particularly useful to perform this task. Fully automatized methods have ... More
Finding New High-Redshift Quasars by Asking the NeighboursOct 26 2012Quasars with a high redshift (z) are important to understand the evolution processes of galaxies in the early universe. However only a few of these distant objects are known to this date. The costs of building and operating a 10-metre class telescope ... More
Uncertain Photometric RedshiftsAug 29 2016Photometric redshifts play an important role as a measure of distance for various cosmological topics. Spectroscopic redshifts are only available for a very limited number of objects but can be used for creating statistical models. A broad variety of ... More
Multiple Interactions in Herwig++Jun 26 2008In this contribution we describe a new model of multiple partonic interactions that has been implemented in Herwig++. Tuning its two free parameters we find a good description of CDF underlying event data. We show extrapolations to the LHC and discuss ... More
Simulation of multiple partonic interactions in Herwig++Mar 26 2008Jun 17 2008In this paper we describe a new model of multiple partonic interactions that has been implemented in Herwig++. Tuning its two free parameters we find a good description of CDF underlying event data. We show extrapolations to the LHC.
A model of non-perturbative gluon emission in an initial state parton showerDec 07 2007May 27 2008We consider a model of transverse momentum production in which non-perturbative smearing takes place throughout the perturbative evolution, by a simple modification to an initial state parton shower algorithm. Using this as the important non-perturbative ... More
The Process γ^{*}_L+ q \to q\bar{q}g + q: Real Corrections to the Virtual Photon Impact FactorJul 13 2001We calculate, for the longitudinally polarized virtual photon, the cross section of the process \gamma^{*}+q\to (q\bar{q}g)+q at high energies with a large rapidity gap between the fragmentation system q\bar{q}g and the other quark. This process provides ... More
Towards Diffraction in HerwigFeb 15 2016We propose changes to the colour reconnection model in the Monte Carlo event generator Herwig in order to remove the quasi diffractive events from the soft multiple parton interactions. We then implement explicitly soft diffraction and show some preliminary ... More
Vector-boson pair production and electroweak corrections in HERWIG++Jan 16 2014The detailed study of vector-boson pair production processes at the LHC will lead to a better understanding of electroweak physics. As pointed out before, a consistent inclusion of higher-order electroweak effects in the analysis of corresponding experimental ... More
Sacrificing information for the greater good: how to select photometric bands for optimal accuracyNov 17 2015Jul 06 2016Large-scale surveys make huge amounts of photometric data available. Because of the sheer amount of objects, spectral data cannot be obtained for all of them. Therefore it is important to devise techniques for reliably estimating physical properties of ... More
Massively-Parallel Break Detection for Satellite DataJul 04 2018The field of remote sensing is nowadays faced with huge amounts of data. While this offers a variety of exciting research opportunities, it also yields significant challenges regarding both computation time and space requirements. In practice, the sheer ... More
Bigger Buffer k-d Trees on Multi-Many-Core SystemsDec 09 2015A buffer k-d tree is a k-d tree variant for massively-parallel nearest neighbor search. While providing valuable speed-ups on modern many-core devices in case both a large number of reference and query points are given, buffer k-d trees are limited by ... More
Big Universe, Big Data: Machine Learning and Image Analysis for AstronomyApr 15 2017Astrophysics and cosmology are rich with data. The advent of wide-area digital cameras on large aperture telescopes has led to ever more ambitious surveys of the sky. Data volumes of entire surveys a decade ago can now be acquired in a single night and ... More
Deep-Learnt Classification of Light CurvesSep 19 2017Astronomy light curves are sparse, gappy, and heteroscedastic. As a result standard time series methods regularly used for financial and similar datasets are of little help and astronomers are usually left to their own instruments and techniques to classify ... More
The new Monte Carlo Event Generator Herwig++Aug 03 2004We present results obtained with the new Monte Carlo event generator Herwig++. In its first version (1.0), Herwig++ is capable of simulating e+e- Annihilation events. We compare results for different distributions with a vast amount of available data ... More
Soft interactions in Herwig++May 28 2009We describe the recent developments to extend the multi-parton interaction model of underlying events in Herwig++ into the soft, non-perturbative, regime. This allows the program to describe also minimum bias collisions in which there is no hard interaction, ... More
Revisiting Radiation Patterns in $e^+e^-$ CollisionsFeb 13 2014We propose four simple event-shape variables for semi-inclusive $e^+e^- \to 4$-jet events. The observables and cuts are designed to be especially sensitive to subleading aspects of the event structure, and allow to test the reliability of phenomenological ... More
Detecting Quasars in Large-Scale Astronomical SurveysAug 23 2011We present a classification-based approach to identify quasi-stellar radio sources (quasars) in the Sloan Digital Sky Survey and evaluate its performance on a manually labeled training set. While reasonable results can already be obtained via approaches ... More
Status of the NLO Corrections to the Photon Impact FactorJun 20 2002We present the status of the programme of calculating the next-to-leading order corrections to the virtual photon impact factor. In particular, we discuss new results for the transversely polarized photon. We briefly outline the definition of infrared ... More
Herwig++ for e+e- collisionsAug 03 2004Some results obtained with the new Monte Carlo event generator Herwig++ are presented. In its first version (1.0), Herwig++ is capable of simulating e+e- Annihilation events. We discuss its relevance for future e+e- colliders and show results on the multiplicity ... More
Topological order of mixed states in quantum many-body systemsSep 08 2016Topological order has become a new paradigm to distinguish ground states of interacting many-body systems without conventional long-range order. Here we discuss possible extensions of this concept to density matrices describing statistical ensembles. ... More
Modulus of continuity of averages of SRB measures for a transversal family of piecewise expanding unimodal mapsApr 12 2016Let $f_t:[0,1] \to [0,1]$ be a family of piecewise expanding unimodal maps with a common critical point that is dense for almost all $t \in [a,b]$. If $\mu_t$ is the corresponding SRB measure for $f_t$, we study the regularity of $\Gamma(t)=\int \phi ... More
Polynomial Separating Algebras and Reflection GroupsJul 29 2013This note considers a finite algebraic group $G$ acting on an affine variety $X$ by automorphisms. Results of Dufresne on polynomial separating algebras for linear representations of $G$ are extended to this situation. For that purpose, we show that the ... More
Leafwise fixed points for $C^0$-small Hamiltonian flows and local coisotropic Floer homologyAug 20 2014Sep 10 2015Consider a closed coisotropic submanifold $N$ of a symplectic manifold $(M,\omega)$ and a Hamiltonian diffeomorphism $\phi$ on $M$. The main result of this article is that $\phi$ has a leafwise fixed point with respect to $N$, provided that it is the ... More
Hilbert-Samuel multiplicities of certain deformation ringsDec 20 2012Mar 31 2014We compute presentations of crystalline framed deformation rings of a two dimensional representation $\bar{\rho}$ of the absolute Galois group of $\mathbb{Q}_p$, when $\bar{\rho}$ has scalar semi-simplification, the Hodge-Tate weights are small and $p>2$. ... More
Distributed Graph AutomataApr 25 2014Inspired by distributed algorithms, we introduce a new class of finite graph automata that recognize precisely the graph languages definable in monadic second-order logic. For the cases of words and trees, it has been long known that the regular languages ... More
Weakly coupled N=4 Super Yang-Mills and N=6 Chern-Simons theories from u(2|2) Yangian symmetryOct 21 2008In this paper we derive the universal R-matrix for the Yangian Y(u(2|2)), which is an abstract algebraic object leading to rational solutions of the Yang-Baxter equation on representations. We find that on the fundamental representation the universal ... More
The final log canonical model of $\bar{M}_6$Mar 27 2013We describe the birational model of $\bar{M}_6$ given by quadric hyperplane sections of the degree 5 del Pezzo surface. In the spirit of the genus 4 case treated by Fedorchuk, we show that it is the last non-trivial space in the log minimal model program ... More
Estimation of state-dependent jump activity and drift for Markovian semimartingalesNov 15 2018Jun 26 2019The jump behavior of an infinitely active It\^o semimartingale can be conveniently characterized by a jump activity index of Blumenthal-Getoor type, typically assumed to be constant in time. We study Markovian semimartingales with a non-constant, state-dependent ... More
Recent progress in the partial-wave analysis of the diffractively produced $π^-π^+π^-$ final state at COMPASSAug 28 2018The COMPASS spectrometer at CERN has collected a large data set for diffractive three-pion production of $46\times10^6$ exclusive events. Based on previous conventional Partial-Wave Analyses (PWA), we performed a `freed-isobar PWA' on the same data, removing ... More
Note on local coisotropic Floer homology and leafwise fixed pointsJul 14 2017I outline a construction of a local Floer homology for a coisotropic submanifold of a symplectic manifold and explain how it can be used to show that leafwise fixed points of Hamiltonian diffeomorphisms exist.
Separating Invariants of Finite GroupsApr 13 2017This paper studies separating invariants of finite groups acting on affine varieties through automorphisms. Several results, proved by Serre, Dufresne, Kac-Watanabe and Gordeev, and Jeffries and Dufresne exist that relate properties of the invariant ring ... More
The effect of relative velocity and density perturbations between baryons and dark matter on the clustering of galaxiesFeb 29 2016Aug 24 2016Pre-recombination acoustic oscillations induce non-adiabatic perturbations between baryons and dark matter, corresponding to a constant relative-density $\delta_{bc}$ and decaying relative-velocity perturbation $\vec{v}_{bc}$. Due to their significant ... More
Towards a self-consistent halo model for the nonlinear large-scale structureNov 06 2015Feb 17 2016The halo model is a theoretically and empirically well-motivated framework for predicting the statistics of the nonlinear matter distribution in the Universe. However, current incarnations of the halo model suffer from two major deficiencies: $(i)$ they ... More
Monodromic Dark EnergySep 05 2017Oct 06 2017Since the discovery of the accelerated expansion of the Universe, the constraints on the equation of state $w_\text{DE}$ of dark energy, the stress-energy component responsible for the acceleration, have tightened significantly. These constraints generally ... More
Hadron Physics at the COMPASS ExperimentDec 08 2014Quantum Chromodynamics (QCD), the theory of strong interactions, in principle describes the interaction of quark and gluon fields. However, due to the self-coupling of the gluons, quarks and gluons are confined into hadrons and cannot exist as free particles. ... More
A remark on a relation between foliations and number theoryMay 07 2006We interpret a formula for meromorphic functions on foliations by Riemann surfaces as an analogue to the product formula of valuations in algebraic number theory.
Classification of Hamiltonian group actions on exact symplectic manifolds with proper momentum mapsJun 25 2018Jul 31 2018Let $G$ be a compact and connected Lie group. The $G$-model functor maps the category of symplectic representations of closed subgroups of $G$ to the category of exact Hamiltonian $G$-actions. Based on previous joint work with Y. Karshon, the restriction ... More
Fourier coefficients of half-integral weight cusp forms and Waring's problemJun 28 2017Extending the approach of Iwaniec and Duke, we present strong uniform bounds for Fourier coefficients of half-integral weight cusp forms of level $N$. As an application, we consider a Waring-type problem with sums of mixed powers.
Valuations on Log-Concave FunctionsJul 20 2017A classification of $\operatorname{SL}(n)$ and translation covariant Minkowski valuations on log-concave functions is established. The moment vector and the recently introduced level set body of log-concave functions are characterized. Furthermore, analogs ... More
The nonlinear stochastic Schrödinger equation via stochastic Strichartz estimatesNov 22 2016We consider the stochastic NLS with linear multiplicative noise in $L^2(\mathbb{R}^d)$ and prove the existence and uniqueness of a global solution in the subcritical and a local solution in the critical case, respectively. In particular, we relax the ... More
Towards the Integration of an Intuitionistic First-Order Prover into CoqJun 20 2016An efficient intuitionistic first-order prover integrated into Coq is useful to replay proofs found by external automated theorem provers. We propose a two-phase approach: An intuitionistic prover generates a certificate based on the matrix characterization ... More
Framework of two-dimensional functional walksSep 14 2017This paper gives a general introduction to two-dimensional functional walks with particular attention to notation and definition. We also give applications of functional walks and a visual overview of some walks generated by $f(n)=n^2$ and $f(n)=n^3$. ... More
Light-Meson Spectroscopy at COMPASSNov 04 2016The goal of the COMPASS experiment at CERN is to study the structure and spectroscopy of hadrons. The two-stage spectrometer has large acceptance and covers a wide kinematic range for charged as well as neutral particles allowing to access a wide range ... More
What is an Ontology?Oct 22 2018In the knowledge engineering community "ontology" is usually defined in the tradition of Gruber as an "explicit specification of a conceptualization". Several variations of this definition exist. In the paper we argue that (with one notable exception) ... More
Families of $\mathcal D$-modulesAug 31 2018We develop a theory of $\mathcal D$-modules over general bases with an emphasis on functorial aspects, i.e.\ we study base change properties and descent problems. In particular, we establish a flat base change theorem as well as faithfully flat descent ... More
The Transient program of the Cherenkov Telescope ArrayJul 17 2019The Cherenkov Telescope Array (CTA) is the next generation high-energy gamma-ray observatory. It will improve the sensitivity of current instruments up to an order of magnitude, while providing energy coverage for photons from 20 GeV to at least 300 TeV ... More
The self-justifying Elo rating systemJan 07 2018We suggest an improvement of the Elo rating system. Whereas Elo's theoretical background remains unaffected, we significantly change the way in which rating values are adjusted. It turns out that the modified system behaves much more naturally, and that ... More
On p-adic L-functions for ${\rm GL}(n)\times{\rm GL}(n-1)$ over totally real fieldsNov 08 2011May 02 2014We refine and extend previous constructions of $p$-adic $L$-functions for Rankin-Selberg convolutions on $\GL(n)\times\GL(n-1)$ for regular algebraic representations over totally real fields. We also prove an intrinsic functional equation for this $p$-adic ... More
p-adic L-functions for Rankin-Selberg convolutions over number fieldsJan 19 2015We unconditionally construct cyclotomic p-adic L-functions for Rankin-Selberg convolutions for GL(n+1) x GL(n) over arbitrary number fields, and show that they satisfy an expected functional equation.
Non-Gaussian Halo Bias Beyond the Squeezed LimitApr 05 2013Jun 13 2013Primordial non-Gaussianity, in particular the coupling of modes with widely different wavelengths, can have a strong impact on the large-scale clustering of tracers through a scale-dependent bias with respect to matter. We demonstrate that the standard ... More
Algebraic Characters for Harish-Chandra modulesJan 12 2012Oct 25 2013We give a cohomological treatment of a character theory for (g,K)-modules. This leads to a nice formalism extending to large categories of not necessarily admissible (g,K)-modules. Due to results of Hecht, Schmid and Vogan the classical results of Harish-Chandra's ... More
On some dyadic models of the Euler equationsOct 17 2004Oct 19 2004Katz and Pavlovic recently proposed a dyadic model of the Euler equations for which they proved finite time blow-up in the $H^{3/2+\epsilon}$ Sobolev norm. It is shown that their model can be reduced to the dyadic inviscid Burgers equation where nonlinear ... More
Measurements of the Muon Content of UHECR Air Showers with the Pierre Auger ObservatoryFeb 26 2009The Pierre Auger Observatory, recently completed, has been operational since 2004. As a hybrid experiment, it allows for a wide range of measurements of UHECR-induced extensive air showers (EAS), including measurements of the EAS particle content on ground ... More
The nonlinear stochastic Schrödinger equation via stochastic Strichartz estimatesNov 22 2016Sep 15 2017We consider the stochastic NLS with nonlinear Stratonovic noise for initial values in $L^2(R^d)$ and prove local existence and uniqueness of a mild solution for subcritical and critical nonlinearities. The proof is based on deterministic and stochastic ... More
The hippocampal-striatal circuit for goal-directed and habitual choiceDec 09 2014It is now widely accepted that one of the roles of the hippocampus is to maintain episodic spatial representations, while parallel striatal pathways contribute to both declarative and procedural value computations by encoding different input-specific ... More
Tearing of thin sheets: Cracks interacting through an elastic ridgeSep 01 2014Dec 17 2014We study the interaction between two cracks propagating quasistatically during the tearing of a thin brittle sheet. We show that the cracks attract each other following a path described by a power law resulting from the competition between elastic and ... More
Vector bundles and Arakelov geometry on the projective line over the integersAug 12 2014We study locally free sheaves of rank two on the projective line over the integers, especially indecomposable ones. Subsequently we apply various concepts of Arakelov geometry to these sheaves. We compute for example the arithmetic Chern classes and use ... More
The symplectic structure on the moduli space of line bundles on a noncommutative Azumaya surfaceNov 10 2015In this note we prove that the moduli space of torsion-free modules of rank one over an Azumaya algebra on a K3-surface is an irreducible symplectic variety deformation equivalent to a Hilbert scheme of points on the K3-surface.
Two Embedding Theorems for Data with Equivalences under Finite Group ActionJul 30 2012Oct 15 2012There is recent interest in compressing data sets for non-sequential settings, where lack of obvious orderings on their data space, require notions of data equivalences to be considered. For example, Varshney & Goyal (DCC, 2006) considered multiset equivalences, ... More
On the convergence rate of the three operator splitting schemeOct 25 2016The three operator splitting scheme was recently proposed by [Davis and Yin, 2015] as a method to optimize composite objective functions with one convex smooth term and two convex (possibly non-smooth) terms for which we have access to their proximity ... More
Topological order of mixed states in quantum many-body systemsSep 08 2016Jan 16 2017Topological order has become a new paradigm to distinguish ground states of interacting many-body systems without conventional long-range order. Here we discuss possible extensions of this concept to density matrices describing statistical ensembles. ... More
Theoretical Investigation of C_60 IR SpectrumFeb 16 1996Feb 19 1996A semi-empirical model of the infrared (IR) spectrum of the C$_{60}$ molecule is proposed. The weak IR-active modes seen experimentally in a C$_{60}$ crystalline sample are argued to be combination modes caused by anharmonicity. The origin of these 2-mode ... More
Moments of Spinor L-Functions and symplectic Kloosterman sumsMay 29 2018We compute the second moment of spinor $L$-functions at central points of Siegel modular forms on congruence subgroups of large prime level $N$ and give applications to non-vanishing.
The pullback of a theta divisor to M_{g,n}Mar 14 2012Jan 07 2013We compute the class of a divisor on M_{g,n} given as the closure of the locus of smooth pointed curves [C; x_1,..., x_n] for which \sum d_j x_j has an effective representative, where d_j are integers summing up to g-1, not all positive. The techniques ... More
Searches for Lorentz-Violating Signals with Astrophysical Polarization MeasurementsJul 15 2019Astrophysical observations are a powerful tool to constrain effects of Lorentz-invariance violation in the photon sector. Objects at high redshifts provide the longest possible baselines, and gamma-ray telescopes allow us to observe some of the highest ... More
On an Exact and Nonparametric Test for the Separability of Two Classes by Means of a Simple ThresholdJul 14 2017This paper introduces a statistical test inferring whether a variable allows separating two classes by means of a single critical value. Its test statistic is the prediction error of a nonparametric threshold classifier. While this approach is adequate ... More
Cosmological Simulations of Normal-Branch Braneworld GravityOct 01 2009Aug 01 2018We introduce a cosmological model based on the normal branch of DGP braneworld gravity with a smooth dark energy component on the brane. The expansion history in this model is identical to LambdaCDM, thus evading all geometric constraints on the DGP cross-over ... More
Algebraic Characters of Harish-Chandra Modules and ArithmeticityOct 25 2013These are expanded notes from lectures at the Workshop "Representation Theory and Applications" held at Yeditepe University, Istanbul, in honor of Roger E. Howe. They are supplemented by the application of algebraic character theory to the construction ... More
Almost every vector valued modular form is an oldformJan 23 2014Jan 27 2014In this article we show that 'most' of the vector valued modular forms w.r.t. the Weil representation on the groups rings $\mathbb{C}[D]$ of discriminant forms D are oldforms. The precise meaning of oldform is that the form can be represented as a sum ... More
Volume, Polar Volume and Euler Characteristic for Convex FunctionsJun 28 2018Functional analogs of the Euler characteristic and volume together with a new analog of the polar volume are characterized as non-negative, continuous, $\operatorname{SL}(n)$ and translation invariant valuations on the space of finite, convex and coercive ... More
Moments of Spinor L-Functions and symplectic Kloosterman sumsMay 29 2018May 29 2019We compute the second moment of spinor $L$-functions at central points of Siegel modular forms on congruence subgroups of large prime level $N$ and give applications to non-vanishing.
A Quantum Kirwan Map, II: BubblingJun 09 2011Sep 27 2012Consider a Hamiltonian action of a compact connected Lie group $G$ on an aspherical symplectic manifold $(M,\omega)$. Under suitable assumptions, counting gauge equivalence classes of (symplectic) vortices on the plane $R^2$ conjecturally gives rise to ... More
A Quantum Kirwan Map, I: Fredholm TheoryMay 25 2009Sep 27 2012Consider a Hamiltonian action of a compact connected Lie group $G$ on an aspherical symplectic manifold $(M,\omega)$. Under some assumptions on $(M,\omega)$ and the action, D. A. Salamon conjectured that counting gauge equivalence classes of symplectic ... More
The Invariant Symplectic Action and Decay for VorticesNov 24 2006Sep 08 2008The (local) invariant symplectic action functional $\A$ is associated to a Hamiltonian action of a compact connected Lie group $\G$ on a symplectic manifold $(M,\omega)$, endowed with a $\G$-invariant Riemannian metric $<\cdot,\cdot>_M$. It is defined ... More
Remarks on a quasi-linear model of the Navier-Stokes EquationsSep 19 2004Dinaburg and Sinai recently proposed a quasi-linear model of the Navier-Stokes equations. Their model assumes that nonlocal interactions in Fourier space are dominant, contrary to the Kolmogorov turbulence phenomenology where local interactions prevail. ... More
Rate-optimal estimation of the Blumenthal-Getoor index of a Lévy processJun 19 2019The Blumenthal-Getoor (BG) index characterizes the jump measure of an infinitely active L\'evy process. It determines sample path properties and affects the behavior of various econometric procedures. If the process contains a diffusion term, existing ... More
The cubo-cubic transformation and K3 surfacesAug 15 2019In this note we observe that the Cremona transformation in Oguiso's example of Cremona isomorphic but not projectively equivalent quartic K3 surfaces in three-dimensional projective space is the classical cubo-cubic transformation.
Cosmological Simulations of Normal-Branch Braneworld GravityOct 01 2009Nov 30 2009We introduce a cosmological model based on the normal branch of DGP braneworld gravity with a smooth dark energy component on the brane. The expansion history in this model is identical to LambdaCDM, thus evading all geometric constraints on the DGP cross-over ... More
spikeSlabGAM: Bayesian Variable Selection, Model Choice and Regularization for Generalized Additive Mixed Models in RMay 26 2011The R package spikeSlabGAM implements Bayesian variable selection, model choice, and regularized estimation in (geo-)additive mixed models for Gaussian, binomial, and Poisson responses. Its purpose is to (1) choose an appropriate subset of potential covariates ... More
Convergence of the risk for nonparametric IV quantile regression and nonparametric IV regression with full independenceNov 12 2015In econometrics some nonparametric instrumental regression models and nonparametric demand models with endogeneity lead to nonlinear integral equations with unknown integral kernels. We prove convergence rates of the risk for the iteratively regularized ... More
Gravitational Infall onto Molecular Filaments II. Externally Pressurized CylindersAug 26 2013In an extension of Fischera & Martin (2012a) and Heitsch (2013), two aspects of the evolution of externally pressurized, hydrostatic filaments are discussed. (a) The free-fall accretion of gas onto such a filament will lead to filament parameters (specifically, ... More
On Rational Structures on Automorphic RepresentationsNov 12 2014Aug 18 2016We prove the existence of global rational structures on spaces of cusp forms of general reductive groups. We identify cases where the constructed rational structures are optimal, which includes the case of GL(n). As an application we deduce the existence ... More
Distributed Graph Automata and Verification of Distributed AlgorithmsAug 13 2014Sep 28 2014Combining ideas from distributed algorithms and alternating automata, we introduce a new class of finite graph automata that recognize precisely the languages of finite graphs definable in monadic second-order logic. By restricting transitions to be nondeterministic ... More
Interleaved entropy codersFeb 14 2014The ANS family of arithmetic coders developed by Jarek Duda has the unique property that encoder and decoder are completely symmetric in the sense that a decoder reading bits will be in the exact same state that the encoder was in when writing those bits---all ... More
An incidence Hopf Algebra of Convex GeometriesDec 05 2012A lattice L is "meet-distributive" if for each element of L, the meets of the elements directly below it form a Boolean lattice. These objects are in bijection with "convex geometries", which are an abstract model of convexity. Do they give rise to an ... More
Alternating Set Quantifiers in Modal LogicFeb 29 2016We establish the strictness of several set quantifier alternation hierarchies that are based on modal logic, evaluated on various classes of finite graphs. This extends to the modal setting a celebrated result of Matz, Schweikardt and Thomas (2002), which ... More
Hyperparameter optimization with approximate gradientFeb 07 2016Jun 26 2016Most models in machine learning contain at least one hyperparameter to control for model complexity. Choosing an appropriate set of hyperparameters is both crucial in terms of model accuracy and computationally challenging. In this work we propose an ... More
On the convergence rate of the three operator splitting schemeOct 25 2016Dec 02 2016The three operator splitting scheme was recently proposed by [Davis and Yin, 2015] as a method to optimize composite objective functions with one convex smooth term and two convex (possibly non-smooth) terms for which we have access to their proximity ... More
A local proof of the Breuil-Mézard conjecture in the scalar semi-simplification caseJun 03 2015We give a new local proof of the Breuil-M\'ezard conjecture in the case of a reducible representation of the absolute Galois group of $\mathbb{Q}_p$, $p>2$, that has scalar semi-simplification, via a formalism of Pa\v{s}k\=unas.
Reverse Reconciliation Continuous Variable Quantum Key Distribution Based on the Uncertainty PrincipleMay 23 2014Nov 18 2014A big challenge in continuous variable quantum key distribution is to prove security against arbitrary coherent attacks including realistic assumptions such as finite-size effects. Recently, such a proof has been presented in [Phys. Rev. Lett. 109, 100502 ... More
Existence of Minimizers in Restricted Hartree-Fock TheoryJun 21 2012In this note we establish the existence of ground states for atoms within several restricted Hartree-Fock theories. It is shown, for example, that there exists a ground state for closed shell atoms with $N$ electrons and nuclear charge $Z \geq N-1$. This ... More
Dust in the Early (z>1) UniverseApr 01 2009Although dust emission at cosmological distances has only been detected a little more than a decade ago, remarkable progress has been achieved since then in characterizing the far-infrared emission of high-redshift systems. The mere fact that dust can ... More
Hermitian Azumaya modules and arithmetic Chern classesJul 27 2016We compute arithmetic Chern classes of sheaves on an arithmetic surface X associated to a Hermitian Azumaya algebra.
Modular symbols for reductive groups and p-adic Rankin-Selberg convolutions over number fieldsMar 09 2009May 27 2009We give a construction of a wide class of modular symbols attached to reductive groups. As an application we construct a p-adic distribution interpolating the special values of the twisted Rankin-Selberg L-function attached to cuspidal automorphic representations ... More