Results for "Thomas Kupfer"

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HD 49798: Its History of Binary Interaction and Future EvolutionAug 22 2017Sep 28 2017The bright subdwarf-O star (sdO), HD 49798, is in a 1.55 day orbit with a compact companion that is spinning at 13.2 seconds. Using the measurements of the effective temperature ($T_{\rm eff}$), surface gravity ($\log g$), and surface abundances of the ... More
Variability of Red Supergiants in M31 from the Palomar Transient FactoryMar 27 2018Most massive stars end their lives as Red Supergiants (RSGs), a short-lived evolution phase when they are known to pulsate with varying amplitudes. The RSG period-luminosity (PL) relation has been measured in the Milky Way, the Magellanic Clouds and M33 ... More
The Zwicky Transient Facility: Surveys and SchedulerMay 06 2019We present a novel algorithm for scheduling the observations of time-domain imaging surveys. Our Integer Linear Programming approach optimizes an observing plan for an entire night by assigning targets to temporal blocks, enabling strict control of the ... More
Measurement of Magnetic Relaxation in the peak regime of V3SiSep 22 2003Magnetization relaxation measurements are carried out in the Peak effect regime of superconducting V3Si crystal, using Quantum Design SQUID magnetometer. Relaxation in the increasing field scan is logarithmic in time, consistent with the theory of flux ... More
The Binary Dwarf Carbon Star SDSS J125017.90+252427.6Mar 02 2018Although dwarf carbon (dC) stars are thought universally to be binaries to explain the presence of $C_2$ in their spectra while still near main sequence luminosity, direct observational evidence for binarity is remarkably scarce. Here we report the detection ... More
Hot subdwarf binaries - Masses and nature of their heavy compact companionsJan 13 2009Neutron stars and stellar-mass black holes are the remnants of massive stars, which ended their lives in supernova explosions. These exotic objects can only be studied in relatively rare cases. If they are interacting with close companions they become ... More
Quantitative spectroscopy of extreme helium stars - Model atmospheres and a non-LTE abundance analysis of BD+10$^\circ$2179?Jun 16 2017Extreme helium stars (EHe stars) are hydrogen-deficient supergiants of spectral type A and B. They are believed to result from mergers in double degenerate systems. In this paper we present a detailed quantitative non-LTE spectral analysis for BD+10$^\circ$2179, ... More
A Note on the Ratio of Revenues Between Selling in a Bundle and SeparatelyNov 29 2016We consider the problem of maximizing revenue when selling k items to a single buyer with known valuation distributions. We show that for a single, additive buyer whose valuations for for the items are distributed according to i.i.d. distributions which ... More
An extremely fast halo hot subdwarf star in a wide binary systemApr 11 2016New spectroscopic observations of the halo hyper-velocity star candidate SDSS J121150.27+143716.2 ($V=17.92$ mag) revealed a cool companion to the hot subdwarf primary. The components have a very similar radial velocity and their absolute luminosities ... More
Astro2020 Science White Paper: A Summary of Multimessenger Science with Galactic BinariesApr 02 2019Galactic binaries with orbital periods less than $\approx$1 hr are strong gravitational wave sources in the mHz regime, ideal for the Laser Interferometer Space Antenna (LISA). In fact, theory predicts that \emph{LISA} will resolve tens of thousands of ... More
Towards Efficient Detection of Small Near-Earth Asteroids Using the Zwicky Transient Facility (ZTF)Apr 21 2019We describe ZStreak, a semi-real-time pipeline specialized in detecting small, fast-moving near-Earth asteroids (NEAs) that is currently operating on the data from the newly-commissioned Zwicky Transient Facility (ZTF) survey. Based on a prototype originally ... More
A multi-wavelength approach to classifying transient events in the direction of M31Mar 30 2018(abridged) In the hunt for rare time-domain events, confusing exotic extragalactic phenomena with more common Galactic foreground events is an important consideration. We show how observations from multiple wavebands, in this case optical and X-ray observations, ... More
Multimessenger science opportunities with mHz gravitational wavesMar 11 2019LISA will open the mHz band of gravitational waves (GWs) to the astronomy community. The strong gravity which powers the variety of GW sources in this band is also crucial in a number of important astrophysical processes at the current frontiers of astronomy. ... More
A New Class of Changing-Look LINERsApr 24 2019We report the discovery of six active galactic nuclei (AGN) caught "turning on" during the first nine months of the Zwicky Transient Facility (ZTF) survey. The host galaxies were classified as LINERs by weak narrow forbidden line emission in their archival ... More
A novel method for transient detection in high-cadence optical surveys: Its application for a systematic search for novae in M31Dec 01 2016[abridged] In large-scale time-domain surveys, the processing of data, from procurement up to the detection of sources, is generally automated. One of the main challenges is contamination by artifacts, especially in regions of strong unresolved emission. ... More
Astro2020 Decadal Science White Paper: Gravitational Wave Survey of Galactic Ultra Compact BinariesMar 13 2019Ultra-compact binaries (UCBs) are systems containing compact or degenerate stars with orbital periods less than one hour. Tens of millions of UCBs are predicted to exist within theGalaxy emitting gravitational waves (GWs) at mHz frequencies. Combining ... More
2900 square degree search for the optical counterpart of short gamma-ray burst GRB 180523B with the Zwicky Transient FacilityJan 31 2019There is significant interest in the models for production of short gamma-ray bursts. Until now, the number of known short gamma-ray bursts with multi-wavelength afterglows has been small. While the {\it Fermi} Gamma-Ray Burst Monitor detects many gamma-ray ... More
Five New Outbursting AM CVn Systems Discovered by the Palomar Transient FactoryDec 21 2012We present five new outbursting AM CVn systems and one candidate discovered as part of an ongoing search for such systems using the Palomar Transient Factory (PTF). This is the first large-area, systematic search for AM CVn systems using only large-amplitude ... More
Machine Learning for the Zwicky Transient FacilityFeb 05 2019The Zwicky Transient Facility is a large optical survey in multiple filters producing hundreds of thousands of transient alerts per night. We describe here various machine learning (ML) implementations and plans to make the maximal use of the large data ... More
Multiple Outbursts of Asteroid (6478) GaultMar 13 2019Main-belt asteroid (6478) Gault unexpectedly sprouted two tails in late 2018 and early 2019, identifying it as a new active asteroid. Here we present observations obtained by the 1.2-m Zwicky Transient Facility survey telescope that provide detailed time-series ... More
Confirmation of Large Super-Fast Rotator (144977) 2005 EC127Apr 27 2017(144977) 2005 EC127 is an V-/A-type inner-main-belt asteroid with a diameter of 0.6 +- 0.1 km. Asteroids of this size are believed to have rubble-pile structure, and, therefore, cannot have a rotation period shorter than 2.2 hours. However, our measurements ... More
The Zwicky Transient Facility: Data Processing, Products, and ArchiveFeb 05 2019The Zwicky Transient Facility (ZTF) is a new robotic time-domain survey currently in progress using the Palomar 48-inch Schmidt Telescope. ZTF uses a 47 square degree field with a 600 megapixel camera to scan the entire northern visible sky at rates of ... More
PTF1 J191905.19+481506.2 - A Partially Eclipsing AM CVn System Discovered in the Palomar Transient FactoryFeb 28 2014We report on PTF1 J191905.19+481506.2, a newly discovered, partially eclipsing, outbursting AM CVn system found in the Palomar Transient Factory synoptic survey. This is only the second known eclipsing AM CVn system. We use high-speed photometric observations ... More
Census of the Local Universe (CLU) I: Characterization of Galaxy Catalogs from Preliminary FieldsOct 13 2017We present a Census of the Local Universe (CLU) -- a combination of the largest area H$\alpha$ survey for nearby emission-line galaxies to date as well as a compilation of all publicly available galaxy catalogs out to a distance of 200 Mpc. With the Palomar ... More
Determination of the spatial TDR-sensor characteristics in strong dispersive subsoil using 3D-FEM frequency domain simulations in combination with microwave dielectric spectroscopyNov 16 2006The spatial sensor characteristics of a 6cm TDR flat band cable sensor section was simulated with finite element modelling (High Frequency Structure Simulator-HFSS) under certain conditions: (i) in direct contact to the surrounding material (air, water ... More
The Death Throes of a Stripped Massive Star: An Eruptive Mass-Loss History Encoded in Pre-Explosion Emission, a Rapidly Rising Luminous Transient, and a Broad-Lined Ic Supernova SN2018gepApr 24 2019We present detailed observations of ZTF18abukavn (SN2018gep), discovered in high-cadence data from the Zwicky Transient Facility as a rapidly rising (1.3 mag/hr) and luminous ($M_{g,\mathrm{peak}}=-20$ mag) transient. It is spectroscopically classified ... More
Structure, dynamics and light localization in self-induced plasma photonic latticesDec 05 2013Feb 03 2014Detailed two dimensional particle-in-cell (PIC) simulations and numerical calculations of electron density profiles, based on a simplified model, were performed to show for the first time that underdense plasma, induced by two pairs of counterpropagating ... More
Discovery of 36 eclipsing EL CVn binaries found by the Palomar Transient FactoryDec 18 2017We report the discovery and analysis of 36 new eclipsing EL CVn-type binaries, consisting of a core helium-composition pre-white dwarf and an early-type main-sequence companion, more than doubling the known population of these systems. We have used supervised ... More
Understanding the evolution of close white dwarf binariesMar 11 2019Interacting binaries containing white dwarfs can lead to a variety of outcomes that range from powerful thermonuclear explosions, which are important in the chemical evolution of galaxies and as cosmological distance estimators, to strong sources of low ... More
Astro2020 Science White Paper: Understanding the evolution of close white dwarf binariesMar 11 2019Mar 13 2019Interacting binaries containing white dwarfs can lead to a variety of outcomes that range from powerful thermonuclear explosions, which are important in the chemical evolution of galaxies and as cosmological distance estimators, to strong sources of low ... More
An optimization principle for the computation of MHD equilibria in the solar coronaDec 21 2006AIMS: We develop an optimization principle for computing stationary MHD equilibria. METHODS: Our code for the self-consistent computation of the coronal magnetic fields and the coronal plasma uses non-force-free MHD equilibria. Previous versions of the ... More
Probabilistic Reasoning about Actions in Nonmonotonic Causal TheoriesOct 19 2012We present the language {m P}{cal C}+ for probabilistic reasoning about actions, which is a generalization of the action language {cal C}+ that allows to deal with probabilistic as well as nondeterministic effects of actions. We define a formal semantics ... More
Two-Variable Logic with Two Order RelationsOct 07 2011Mar 03 2012It is shown that the finite satisfiability problem for two-variable logic over structures with one total preorder relation, its induced successor relation, one linear order relation and some further unary relations is EXPSPACE-complete. Actually, EXPSPACE-completeness ... More
On the quantifier-free dynamic complexity of ReachabilityJun 13 2013Jan 28 2015The dynamic complexity of the reachability query is studied in the dynamic complexity framework of Patnaik and Immerman, restricted to quantifier-free update formulas. It is shown that, with this restriction, the reachability query cannot be dynamically ... More
Sélection de la structure d'un perceptron multicouches pour la réduction dun modèle de simulation d'une scierieDec 05 2008Simulation is often used to evaluate the relevance of a Directing Program of Production (PDP) or to evaluate its impact on detailed sc\'enarii of scheduling. Within this framework, we propose to reduce the complexity of a model of simulation by exploiting ... More
Astro2020 Science White Paper: Understanding the evolution of close white dwarf binariesMar 11 2019Mar 15 2019Interacting binaries containing white dwarfs can lead to a variety of outcomes that range from powerful thermonuclear explosions, which are important in the chemical evolution of galaxies and as cosmological distance estimators, to strong sources of low ... More
PTF1 J082340.04+081936.5: A hot subdwarf B star with a low mass white dwarf companion in an 87 minute orbitDec 06 2016We present the discovery of the hot subdwarf B star (sdB) binary PTF1 J082340.04+081936.5. The system has an orbital period P$_{\rm orb}=87.49668(1)$ min (0.060761584(10) days), making it the second-most compact sdB binary known. The lightcurve shows ... More
The Role of Plasma Shielding in Double-Pulse Femtosecond Laser-Induced Breakdown SpectroscopyAug 26 2013It is well known that optical emission produced by femtosecond laser-induced breakdown on a surface may be enhanced by using a pair of laser pulses separated by a suitable delay. Here we elucidate the mechanism for this effect both experimentally and ... More
How deals with discrete data for the reduction of simulation models using neural networkJun 10 2009Simulation is useful for the evaluation of a Master Production/distribution Schedule (MPS). Also, the goal of this paper is the study of the design of a simulation model by reducing its complexity. According to theory of constraints, we want to build ... More
Spectral Correlations in the Crossover Transition from a Superposition of Harmonic Oscillators to the Gaussian Unitary EnsembleJul 20 1998We compute the spectral correlation functions for the transition from a harmonic oscillator towards the Gaussian Unitary Ensemble (GUE). We use a variant of the supersymmetry method to obtain analytical results in a fast and elegant way. In contrast to ... More
Thermodynamic formalism for transport coefficients with an application to the shear modulus and shear viscosityDec 07 2016We discuss Onsager's thermodynamic formalism for transport coefficients and apply it to the calculation of the shear modulus and shear viscosity of a monodisperse system of repulsive particles. We focus on the concept of extensive "distance" and intensive ... More
On the boundedness of an iteration involving points on the hypersphereJan 11 2010Oct 05 2010For a finite set of points $X$ on the unit hypersphere in $\mathbb{R}^d$ we consider the iteration $u_{i+1}=u_i+\chi_i$, where $\chi_i$ is the point of $X$ farthest from $u_i$. Restricting to the case where the origin is contained in the convex hull of ... More
Causes and Explanations in the Structural-Model Approach: Tractable CasesDec 12 2012In this paper, we continue our research on the algorithmic aspects of Halpern and Pearl's causes and explanations in the structural-model approach. To this end, we present new characterizations of weak causes for certain classes of causal models, which ... More
Nef reduction and anticanonical bundlesOct 31 2003We investigate the structure of smooth projective 3-folds X with -K_X nef and K_X^3=0.
Binaries discovered by the SPY project V. GD 687 - a massive double degenerate binary progenitor that will merge within a Hubble timeMar 22 2010Aims. The ESO SN Ia Progenitor Survey (SPY) aims at finding merging double degenerate binaries as candidates for supernova type Ia (SN Ia) explosions. A white dwarf merger has also been suggested to explain the formation of rare types of stars like R ... More
Census of the Local Universe (CLU) Narrow-Band Survey I: Galaxy Catalogs from Preliminary FieldsOct 13 2017May 08 2019We present the Census of the Local Universe (CLU) narrow-band survey to search for emission-line (\ha) galaxies. CLU-\ha~has imaged $\approx$3$\pi$ of the sky (26,470~deg$^2$) with 4 narrow-band filters that probe a distance out to 200~Mpc. We have obtained ... More
The Zwicky Transient Facility: System Overview, Performance, and First ResultsFeb 05 2019The Zwicky Transient Facility (ZTF) is a new optical time-domain survey that uses the Palomar 48-inch Schmidt telescope. A custom-built wide-field camera provides a 47 deg$^2$ field of view and 8 second readout time, yielding more than an order of magnitude ... More
The Zwicky Transient Facility: Science ObjectivesFeb 05 2019The Zwicky Transient Facility (ZTF), a public-private enterprise, is a new time domain survey employing a dedicated camera on the Palomar 48-inch Schmidt telescope with a 47 deg$^2$ field of view and 8 second readout time. It is well positioned in the ... More
Processing Images from the Zwicky Transient FacilityAug 04 2017Oct 16 2017The Zwicky Transient Facility is a new robotic-observing program, in which a newly engineered 600-MP digital camera with a pioneeringly large field of view, 47~square degrees, will be installed into the 48-inch Samuel Oschin Telescope at the Palomar Observatory. ... More
Extremal t processes: Elliptical domain of attraction and a spectral representationJul 10 2012Mar 25 2013The extremal t process was proposed in the literature for modeling spatial extremes within a copula framework based on the extreme value limit of elliptical t distributions (Davison, Padoan and Ribatet (2012)). A major drawback of this max-stable model ... More
Modeling asymptotically independent spatial extremes based on Laplace random fieldsJul 09 2015Mar 08 2016We tackle the modeling of threshold exceedances in asymptotically independent stochastic processes by constructions based on Laplace random fields. These are defined as Gaussian random fields scaled with a stochastic variable following an exponential ... More
Guarantees in Wasserstein Distance for the Langevin Monte Carlo AlgorithmFeb 08 2016Jul 01 2016We study the problem of sampling from a distribution $\target$ using the Langevin Monte Carlo algorithm and provide rate of convergences for this algorithm in terms of Wasserstein distance of order $2$. Our result holds as long as the continuous diffusion ... More
A Classical Realizability Model arising from a Stable Model of Untyped Lambda CalculusJul 06 2014Aug 03 2016We study a classical realizability model (in the sense of J.-L. Krivine) arising from a model of untyped lambda calculus in coherence spaces. We show that this model validates countable choice using bar recursion and bar induction.
Backpropagation of Hebbian plasticity for lifelong learningSep 08 2016Hebbian plasticity allows biological agents to learn from their lifetime experience, extending the fixed information provided by evolutionary search. Conversely, backpropagation methods can build high-performance fixed-weights networks, but are not currently ... More
Minimal Lagrangian connections on compact surfacesSep 26 2016We classify the torsion-free minimal Lagrangian connections on the tangent bundle of a compact oriented surface of non-vanishing Euler characteristic.
Ensemble teleportationApr 15 2004The possibility of teleportation is by sure the most interesting consequence of quantum non-separability. So far, however, teleportation schemes have been formulated by use of state vectors and considering individual entities only. In the present article ... More
Branch dependence in the "consistent histories" approach to quantum mechanicsJun 07 2005Nov 12 2006In the consistent histories formalism one specifies a family of histories as an exhaustive set of pairwise exclusive descriptions of the dynamics of a quantum system. We define branching families of histories, which strike a middle ground between the ... More
For principled model fitting in mathematical biologyApr 21 2014The mathematical models used to capture features of complex, biological systems are typically non-linear, meaning that there are no generally valid simple relationships between their outputs and the data that might be used to validate them. This invalidates ... More
Lie algebra solution of population models based on time-inhomogeneous Markov chainsNov 23 2011Many natural populations are well modelled through time-inhomogeneous stochastic processes. Such processes have been analysed in the physical sciences using a method based on Lie algebras, but this methodology is not widely used for models with ecological, ... More
The Laura++ Dalitz plot fitterMar 02 2016The Laura++ software package is designed for performing fits of amplitude models to data from decays of spin-0 particles into final states containing three spin-0 particles - so-called Dalitz-plot analysis. An overview of the amplitude formalism and its ... More
Numerical Chladni figuresAug 26 2013Chladni patterns of vibrating membranes or thin plates faszinated the people already in the eighteenth century. As a simple way to visualize acoustic phenomena it is a valuable experiment for beginners' courses. In this paper I present NumChladni, an ... More
Homological Descent for Motivic Homology TheoriesJan 30 2014We show that motivic homology, motivic Borel-Moore homology and higher Chow groups satisfy homological descent for hyperenvelopes, and l-hyperenvelopes after inverting l.
Rojtman's theorem for normal schemesFeb 08 2014Feb 25 2015We show that Rojtman's theorem holds for normal schemes: For any reduced normal scheme of finite type over an algebraically closed field, the torsion of the zero'th Suslin homology group agrees with the torsion of the albanese variety (the universal object ... More
A counterexample to the (unstable) Gromov-Lawson-Rosenberg conjectureMar 03 2004Doing surgery on the 5-torus, we construct a 5-dimensional closed spin-manifold M with $\pi_1(M) = Z^4times Z/3$, so that the index invariant in the KO-theory of the reduced $C^*$-algebra of $\pi_1(M)$ is zero. Then we use the theory of minimal surfaces ... More
Operator algebras and topologySep 13 2002These notes cover the contents of three survey lectures held at the ICTP Trieste Summer school on High dimensional manifold theory 2001. They introduce techniques coming from the theory of operator algebras. We will focus on the basic definitions and ... More
L2-index theorem for manifolds with boundaryOct 21 1998Suppose M is a compact manifold with boundary. Let N be a normal covering of M. Suppose (A,T) is an elliptic differential boundary value problem on M with lift (\tilde A,\tilde T) to N. Then the von Neumann dimension of kernel and cokernel of this lift ... More
A Canonical Representation of Data-Linear Visualization AlgorithmsDec 13 2014We introduce linear-state dataflows, a canonical model for a large set of visualization algorithms that we call data-linear visualizations. Our model defines a fixed dataflow architecture: partitioning and subpartitioning of input data, ordering, graphic ... More
Recent Investigations on AA DoradusNov 02 2011AA Dor is an eclipsing, post common-envelope binary with an sdOB-type primary and an unseen low-mass secondary, believed to be a brown dwarf. Eleven years ago, a NLTE spectral analysis of the primary showed a discrepancy with the surface gravity that ... More
Uncertainties in (E)UV model atmosphere fluxesFeb 13 2008During the comparison of synthetic spectra calculated with two NLTE model atmosphere codes, namely TMAP and TLUSTY, we encounter systematic differences in the EUV fluxes due to the treatment of level dissolution by pressure ionization. Systematic differences ... More
High-gravity central starsJul 11 2006NLTE spectral analyses of high-gravity central stars by means of state-of-the-art model atmosphere techniques provide information about the precursor AGB stars. The hydrogen-deficient post-AGB stars allow investigations on the intershell matter which ... More
The First Direct Supernova/GRB Connection: GRB 030329/SN 2003dhSep 29 2003Observations of gamma-ray burst (GRB) afterglows have yielded tantalizing hints that supernovae (SNe) and GRBs are related. The case had been circumstantial, though, relying on irregularities in the light curve or the colors of the afterglow. I will present ... More
Towards a Mori theory on compact Kähler threefolds, IIJul 08 1996This paper, a continuation of ``Towards a Mori theory on compact K\"ahler manifolds, 1'' (written with F. Campana), introduces a non-algebraic analogue to Mori theory in dimension 3.
On rings for which finitely generated ideals have only finitely many componentsJan 23 2006For a commutative ring R we investigate the property that the sets of minimal primes of finitely generated ideals of R is always finite. We prove this property passes to polynomial ring extensions (in an arbitrary number of variables) over R as well as ... More
The Theory of a Heliospheric EconomyMay 30 2015Despite more than 50 years of human space exploration, no paper in the field of economics has been published regarding the theory of a space-based economy. The aim of this paper is to develop quantitative techniques to estimate conditions of the human ... More
There are non homotopic framed homotopies of long knotsOct 23 2007Mar 10 2009Let $\mathcal {M}$ be the space of all, including singular, long knots in 3-space and for which a fixed projection into the plane is an immersion. Let $cl(\Sigma^{(1)}_{iness})$ be the closure of the union of all singular knots in $\mathcal {M}$ with ... More
Knot polynomials via one parameter knot theoryDec 05 2006Feb 06 2007We construct new knot polynomials. Let $V$ be the standard solid torus in 3-space and let $pr$ be its standard projection onto an annulus. Let $M$ be the space of all smooth oriented knots in $V$ such that the restriction of $pr$ is an immersion (e.g. ... More
Global knot theory in F^2 x RDec 12 2000We introduce a special class of knots, called global knots, in F^2 x R and we construct new isotopy invariants, called T-invariants, for global knots. Some T-invariants are of finite type but they cannot be extracted from the generalized Kontsevitch integral ... More
Comment on Gravity and the Poincare GroupFeb 11 1993Following the approach of Grignani and Nardelli [1], we show how to cast the two-dimensional model $L \sim curv^2 + torsion^2 + cosm.const$ -- and in fact any theory of gravity -- into the form of a Poincare gauge theory. By means of the above example ... More
Gravity from Lie algebroid morphismsOct 17 2003Inspired by the Poisson Sigma Model and its relation to 2d gravity, we consider models governing morphisms from TSigma to any Lie algebroid E, where Sigma is regarded as d-dimensional spacetime manifold. We address the question of minimal conditions to ... More
Frechet topologies on hypoelliptic sheavesJul 16 2007Jul 19 2007This note is withdrawn. The result and its proof are available in the literature.
A non-uniform distribution property of most orbits, in case the $3x+1$ conjecture is trueDec 18 2015Let $T(n)=\left\{\begin{array}{ll}3n+1&(n\hbox{ odd})\\\frac n2&(n\hbox{ even})\end{array}\right.$ ($n\in\mathbb Z$). We call "the orbit of the integer $n$", the set $$ \mathcal O_n:=\{m\in\mathbb Z\;:\;\exists k\ge0,\ m=T^k(n)\} $$ and we put $c_i(n):=\#\{m\in\mathcal ... More
Algebraic models for higher categoriesMar 06 2010May 30 2011We introduce the notion of algebraic fibrant objects in a general model category and establish a (combinatorial) model category structure on algebraic fibrant objects. Based on this construction we propose algebraic Kan complexes as an algebraic model ... More
Hadronic Loops versus Factorization in EFT calculations of $X(3872) \to χ_{cJ} π^0$Mar 09 2015Aug 14 2015We compare two existing approaches to calculating the decay of molecular quarkonium states to conventional quarkonia in effective field theory, using $X(3872) \to \chi_{cJ} \pi^0$ as an example. In one approach the decay of the molecular quarkonium proceeds ... More
A Review of Alexander Isaev's Spherical Tube HypersurfacesJan 12 2014Oct 15 2014As this is for the Bulletin of the A.M.S., it is not only a review of Alexander Isaev's Spherical Tube Hypersurfaces but also a brief introduction to CR geometry.
Towards Static Analysis of Functional Programs using Tree Automata CompletionOct 07 2014This paper presents the first step of a wider research effort to apply tree automata completion to the static analysis of functional programs. Tree Automata Completion is a family of techniques for computing or approximating the set of terms reachable ... More
Deformation quantization and the Gerstenhaber structure on the homology of knot spacesJun 23 2015It is well known that (in suitable codimension) the spaces of long knots in $\mathbb{R}^n$ modulo immersions are double loop spaces. Hence the homology carries a natural Gerstenhaber structure, given by the Gerstenhaber structure on the Hochschild homology ... More
The Homotopy Braces Formality MorphismSep 16 2011Oct 03 2015We extend M. Kontsevich's formality morphism to a homotopy braces morphism and to a homotopy Gerstenhaber morphism. We show that this morphism is homotopic to D. Tamarkin's formality morphism, obtained using formality of the little disks operad, if in ... More
M. Kontsevich's graph complex and the Grothendieck-Teichmueller Lie algebraSep 08 2010Dec 23 2013We show that the zeroth cohomology of M. Kontsevich's graph complex is isomorphic to the Grothendieck-Teichmueller Lie algebra grt_1. The map is explicitly described. This result has applications to deformation quantization and Duflo theory. We also compute ... More
Size reduction and partial decoupling of systems of equationsJan 28 2003A method is presented that reduces the number of terms of systems of linear equations (algebraic, ordinary and partial differential equations). As a byproduct these systems have a tendency to become partially decoupled and are more likely to be factorizable ... More
Applications of CRACK in the Classification of Integrable SystemsJan 24 2003Work on different classification problems is described as: the classification of integrable vector evolution equations, NLS systems with two vector unknowns, systems with one scalar and one vector unknown, classification of integrable Hamiltonians and ... More
Interdisciplinary application of nonlinear time series methodsJun 26 1998This paper reports on the application to field measurements of time series methods developed on the basis of the theory of deterministic chaos. The major difficulties are pointed out that arise when the data cannot be assumed to be purely deterministic ... More
On braided tensor categoriesFeb 03 1994We investigate invertible elements and gradings in braided tensor categories. This leads us to the definition of theta-, product-, subgrading and orbitcategories in order to construct new families of BTC's from given ones. We use the representation theory ... More
Uniqueness of the contact structure approximating a foliationFeb 22 2013May 20 2013According to a theorem of Eliashberg and Thurston a $C^2$-foliation on a closed 3-manifold can be $C^0$-approximated by contact structures unless all leaves of the foliation are spheres. Examples on the 3-torus show that every neighbourhood of a foliation ... More
A 64-dimensional two-distance counterexample to Borsuk's conjectureAug 01 2013Aug 20 2014In 1933 Karol Borsuk asked whether each bounded set in the n-dimensional Euclidean space can be divided into n+1 parts of smaller diameter. The diameter of a set is defined as the supremum (least upper bound) of the distances of contained points. Implicitly, ... More
New strongly regular graphs derived from the G2(4) graphSep 11 2014Jun 28 2016We consider simple loopless finite undirected graphs. Such a graph is called strongly regular with parameter set (v,k,l,m), for short a srg(v,k,l,m), iff it has exactly v vertices, each of them has exactly k neighbours, and the number of common neighbours ... More
On spaces with connected Higson coronasFeb 22 2016Apr 10 2016In this paper, we characterise metric spaces which have topologically connected Higson coronas. The characterisation is given by a natural categorical condition applied in the coarse category. We also give a characterisation in terms of coarse cohomology, ... More
Collective behaviours in the stock market -- A maximum entropy approachMar 20 2014Mar 21 2014Scale invariance, collective behaviours and structural reorganization are crucial for portfolio management (portfolio composition, hedging, alternative definition of risk, etc.). This lack of any characteristic scale and such elaborated behaviours find ... More
Market structure explained by pairwise interactionsOct 31 2012Jan 27 2014Financial markets are a typical example of complex systems where interactions between constituents lead to many remarkable features. Here, we show that a pairwise maximum entropy model (or auto-logistic model) is able to describe switches between ordered ... More
Status of QCDJul 13 2010Jul 28 2010In this talk, I review recent developments in perturbative QCD and their applications to collider physics.
Numerical tools to validate stationary points of SO(8)-gauged N=8 D=4 supergravityJul 05 2010Aug 31 2011Until recently, the preferred strategy to identify stationary points in the scalar potential of SO(8)-gauged N=8 supergravity in D=4 has been to consider truncations of the potential to sub-manifolds of E_{7(+7)}/SU(8) that are invariant under some postulated ... More