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Results for "Thomas Cook"

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Heavy quarkonium suppression beyond the adiabatic limitMay 14 2019Many prior studies of in-medium quarkonium suppression have implicitly made use of an adiabatic approximation in which it was assumed that the heavy quark potential is a slowly varying function of time. In the adiabatic limit, one can separately determine ... More
A Concrete View of Rule 110 ComputationJun 17 2009Rule 110 is a cellular automaton that performs repeated simultaneous updates of an infinite row of binary values. The values are updated in the following way: 0s are changed to 1s at all positions where the value to the right is a 1, while 1s are changed ... More
A smooth surface in P4 not of general type has degree at most 46Jan 04 1997This is the continuation of papers by Braun and Floystad, Cook, Braun and Cook. We use Generic Initial Ideal Theory in conjunction with Liaison Theory to further restrict the possible generic initial ideals of hyperplane sections of smooth surfaces not ... More
Orbital Period Increase in ES CetiJan 03 2018We report a long-term study of the eclipse times in the 10-minute helium binary ES Ceti. The binary period increases rapidly, with P/P-dot = 6.2x10^6 yr. This is consistent with the assumption that gravitational radiation (GR) drives the mass transfer, ... More
Predicate Abstraction via Symbolic Decision ProceduresDec 01 2006Apr 24 2007We present a new approach for performing predicate abstraction based on symbolic decision procedures. Intuitively, a symbolic decision procedure for a theory takes a set of predicates in the theory and symbolically executes a decision procedure on all ... More
Excision boundary conditions for the conformal metricOct 24 2008Shibata, Ury\=u and Friedman recently suggested a new decomposition of Einstein's equations that is useful for constructing initial data. In contrast to previous decompositions, the conformal metric is no longer treated as a freely-specifiable variable, ... More
A smooth surface in P4 not of general type has degree at most 66Jan 04 1997We continue the work of Braun and Floystad, and Cook bounding the degree of smooth surfaces in P4 not of general type using generic initial ideal theory.
The circular law for random regular digraphs with random edge weightsAug 02 2015Sep 08 2017We consider random $n\times n$ matrices of the form $Y_n=\frac1{\sqrt{d}}A_n\circ X_n$, where $A_n$ is the adjacency matrix of a uniform random $d$-regular directed graph on $n$ vertices, with $d=\lfloor p n\rfloor$ for some fixed $p \in (0,1)$, and $X_n$ ... More
The structure of the Boij-Söderberg posetsJun 10 2010Boij and S\"oderberg made a pair of conjectures, which were subsequently proven by Eisenbud and Schreyer and then extended by Boij and S\"oderberg, about the structure of Betti diagrams of Graded modules. In the theory, a particular family of posets, ... More
Dense random regular digraphs: singularity of the adjacency matrixMar 24 2014Aug 02 2015Fix $c\in (0,1)$ and let $\Gamma$ be a $\lfloor c n\rfloor$-regular digraph on $n$ vertices drawn uniformly at random. We prove that when $n$ is large, the (non-symmetric) adjacency matrix $M$ of $\Gamma$ is invertible with high probability. The proof ... More
Complexity Theory for Operators in AnalysisMay 02 2013We propose an extension of the framework for discussing the computational complexity of problems involving uncountably many objects, such as real numbers, sets and functions, that can be represented only through approximation. The key idea is to use (a ... More
Proceedings Machines, Computations and Universality 2013Sep 04 2013This volume contains the papers presented at the 6th conference on Machines, Computations and Universality (MCU 2013). MCU 2013 was held in Zurich, Switzerland, September 9-11, 2013. The MCU series began in Paris in 1995 and has since been concerned with ... More
On decomposing Betti tables and $O$-sequencesJul 15 2014The Boij-S\"oderberg characterization decomposes a Betti table into a unique positive integral linear combination of pure diagrams. Given a module with a pure resolution, we describe explicit formulae for computing the decomposition of the Betti table ... More
On the singularity of adjacency matrices for random regular digraphsNov 02 2014Nov 09 2015We prove that the (non-symmetric) adjacency matrix of a uniform random $d$-regular directed graph on $n$ vertices is asymptotically almost surely invertible, assuming $\min(d,n-d)\ge C\log^2n$ for a sufficiently large constant $C>0$. The proof makes use ... More
Cohen-Macaulay graphs and face vectors of flag complexesMar 23 2010Jun 13 2011We introduce a construction on a flag complex that, by means of modifying the associated graph, generates a new flag complex whose $h$-factor is the face vector of the original complex. This construction yields a vertex-decomposable, hence Cohen-Macaulay, ... More
Principal Fitted Components for Dimension Reduction in RegressionJun 22 2009We provide a remedy for two concerns that have dogged the use of principal components in regression: (i) principal components are computed from the predictors alone and do not make apparent use of the response, and (ii) principal components are not invariant ... More
Learning and Inferring Relations in Cortical NetworksAug 29 2016A pressing scientific challenge is to understand how brains work. Of particular interest is the neocortex,the part of the brain that is especially large in humans, capable of handling a wide variety of tasks including visual, auditory, language, motor, ... More
Superhumps in Cataclysmic Binaries. XXV. q_crit, epsilon(q), and Mass-RadiusJul 15 2005We report on successes and failures in searching for positive superhumps in cataclysmic variables, and show the superhumping fraction as a function of orbital period. Basically, all short-period systems do, all long-period systems don't, and a 50% success ... More
Large deviations of subgraph counts for sparse Erdős--Rényi graphsSep 28 2018Dec 10 2018For any fixed, connected graph $H=(V,E)$ of maximum degree $\Delta$ and any fixed $u>0$, we establish the leading order of the exponential rate function for the probability that the number of copies of $H$ in the Erd\H{o}s--R\'enyi graph $G(N,p)$ exceeds ... More
Off The Beaten Lane: AI Challenges In MOBAs Beyond Player ControlJun 09 2017MOBAs represent a huge segment of online gaming and are growing as both an eSport and a casual genre. The natural starting point for AI researchers interested in MOBAs is to develop an AI to play the game better than a human - but MOBAs have many more ... More
Hybrid Exotic Meson Decay WidthSep 12 2005We present results of a decay width calculation for a hybrid exotic meson(h, JPC=1-+) in the decay channel h to pi+a1. This calculation uses quenched lattice QCD and Luescher's finite box method. Operators for the h and pi+a1 states are used in a correlation ... More
Algorithms for Envelope Estimation IISep 12 2015We propose a new algorithm for envelope estimation, along with a new root n consistent method for computing starting values. The new algorithm, which does not require optimization over a Grassmannian, is shown by simulation to be much faster and typically ... More
Two-Phase Galaxy FormationMar 13 2009Apr 28 2009We propose and test a scenario for the assembly and evolution of luminous matter in galaxies which substantially differs from that adopted by other semianalytic models. As for the dark matter (DM), we follow the detailed evolution of halos within the ... More
Lattice QCD study of a five-quark hadronic moleculeApr 18 2007Jul 26 2007We compute the ground-state energies of a heavy-light K-Lambda like system as a function of the relative distance r of the hadrons. The heavy quarks, one in each hadron, are treated as static. Then, the energies give rise to an adiabatic potential Va(r) ... More
Size biased couplings and the spectral gap for random regular graphsOct 20 2015Mar 08 2017Let $\lambda$ be the second largest eigenvalue in absolute value of a uniform random $d$-regular graph on $n$ vertices. It was famously conjectured by Alon and proved by Friedman that if $d$ is fixed independent of $n$, then $\lambda=2\sqrt{d-1} +o(1)$ ... More
Circular law for the sum of random permutation matricesMay 25 2017Apr 04 2018Let $P_n^1,\dots, P_n^d$ be $n\times n$ permutation matrices drawn independently and uniformly at random, and set $S_n^d:=\sum_{\ell=1}^d P_n^\ell$. We show that if $\log^{12}n/(\log \log n)^{4} \le d=O(n)$, then the empirical spectral distribution of ... More
Large dynamic range SPR measurements in the visible using a ZnSe prismMar 24 2015Large dynamic index measurement range (n = 1 to n = 1.7) using surface plasmon resonance (SPR) shifts is demonstrated with a ZnSe prism at 632.8 nm, limited by the available high index liquid hosts. In contrast to borosilicate based SPR measurements where ... More
A Search for Stellar Obscuration Events due to Dark CloudsJan 01 2003The recent detections of a large population of faint submillimetre sources, an excess halo gamma-ray background, and the extreme scattering events observed for extragalactic radio sources have been explained as being due to baryonic dark matter in the ... More
Implementing an apparent-horizon finder in three dimensionsJun 06 1996Locating apparent horizons is not only important for a complete understanding of numerically generated spacetimes, but it may also be a crucial component of the technique for evolving black-hole spacetimes accurately. A scheme proposed by Libson et al., ... More
Multivariate Design of Experiments for Engineering Dimensional AnalysisAug 04 2017Aug 07 2018We consider the design of dimensional analysis experiments when there is more than a single response. We first give a brief overview of dimensional analysis experiments and the dimensional analysis (DA) procedure. The validity of the DA method for univariate ... More
Binary Neutron Stars in Quasi-Equilibrium Circular Orbit: A Fully Relativistic TreatmentJan 14 1997We present a numerical scheme that solves the initial value problem in full general relativity for a binary neutron star in quasi-equilibrium. While Newtonian gravity allows for a strict equilibrium, a relativistic binary system emits gravitational radiation, ... More
Treating instabilities in a hyperbolic formulation of Einstein's equationsJul 14 1998We have recently constructed a numerical code that evolves a spherically symmetric spacetime using a hyperbolic formulation of Einstein's equations. For the case of a Schwarzschild black hole, this code works well at early times, but quickly becomes inaccurate ... More
Numerical Evolution of Black Holes with a Hyperbolic Formulation of General RelativityAug 27 1997We describe a numerical code that solves Einstein's equations for a Schwarzschild black hole in spherical symmetry, using a hyperbolic formulation introduced by Choquet-Bruhat and York. This is the first time this formulation has been used to evolve a ... More
Can a combination of the conformal thin-sandwich and puncture methods yield binary black hole solutions in quasi-equilibrium?Jun 06 2003We consider combining two important methods for constructing quasi-equilibrium initial data for binary black holes: the conformal thin-sandwich formalism and the puncture method. The former seeks to enforce stationarity in the conformal three-metric and ... More
Quasi-equilibrium Binary Black Hole Initial Data for Dynamical EvolutionsJun 04 2004Sep 20 2004We present a formalism for constructing quasi-equilibrium binary black hole initial data suitable for numerical evolution. We construct quasi-equilibrium models by imposing an approximate helical Killing symmetry appropriate for quasi-circular orbits. ... More
Microlensing Optical Depth towards the Galactic Bulge Using Clump Giants from the MACHO SurveyOct 13 2004Jul 29 2005Using 7 years of MACHO survey data, we present a new determination of the optical depth to microlensing towards the Galactic bulge. We select the sample of 62 microlensing events (60 unique) on clump giant sources and perform a detailed efficiency analysis. ... More
Comments on Beckmann's Uniform ReductsJan 19 2006Jan 23 2006Arnold Beckmann defined the uniform reduct of a propositional proof system f to be the set of those bounded arithmetical formulas whose propositional translations have polynomial size f-proofs. We prove that the uniform reduct of f + Extended Frege consists ... More
A note on discrete spherical averages over sparse sequencesAug 11 2018Sep 18 2018This note presents an example of an increasing sequence $(\lambda_l)_{l=1}^\infty$ such that the maximal operators associated to normalized discrete spherical convolution averages \[ \sup_{l\geq 1}\frac{1}{r(\lambda_l)}\left|\sum_{|x|^2=\lambda_l}f(y-x)\right|\] ... More
Discrete multilinear spherical averagesAug 05 2018In this note we give a characterization of $\ell^{p}\times ...\times \ell^{p}\to\ell^q$ boundedness of maximal operators associated to multilinear convolution averages over spheres in $\mathbb{Z}^n$.
Line arrangements and configurations of points with an unusual geometric propertyFeb 06 2016Mar 02 2017The SHGH conjecture proposes a solution to the question of how many conditions a general union of fat points imposes on the complete linear system of curves in $\mathbb P^2$ of fixed degree $d$, and it is known to be true in many cases. We propose a new ... More
Neptune's Latitudinal Variations as Viewed with ALMAMay 08 2019We present spatially resolved millimeter maps of Neptune between 95 and 242 GHz taken with the Atacama Large Millimeter/submillimeter Array (ALMA) in $2016-2017$. The millimeter weighting functions peak between 1 and 10 bar on Neptune, lying in between ... More
An improved bound for the degree of smooth surfaces in P4 not of general type.Jan 16 1995This is an addendum to the paper of Braun and Fl{\o}ystad ([BF]) on the bound for the degree of a smooth surface in $\pfour$ not of general type. Using their construction and the regularity of curves in $\pthree$, one may lower the bound a little more. ... More
Improved $\ell^p$-Boundedness for Integral $k$-Spherical Maximal FunctionsJul 26 2017May 30 2018We improve the range of $\ell^p(\mathbb Z^d)$-boundedness of the integral $k$-spherical maximal functions introduced by Magyar. The previously best known bounds for the full $k$-spherical maximal function require the dimension $d$ to grow at least cubicly ... More
Simulation of Qubit Quantum Circuits via Pauli PropagationJan 25 2019Mar 18 2019We present novel algorithms to estimate outcomes for qubit quantum circuits. Notably, these methods can simulate a Clifford circuit in linear time without ever writing down stabilizer states explicitly. These algorithms outperform previous noisy near-Clifford ... More
New theory of femtosecond induced changes and nanopore formationSep 06 2011Recent results confirm the presence of molecular oxygen proving that recombination of dissociated silica bonds does not occur. This combined with the observation of nanopores within the nanograting structure in silica, leads to a new interpretation of ... More
Resolving the Nature of the LMC Microlensing Event LMC-5Apr 14 2004Apr 19 2004We present the results from an analysis of Hubble Space Telescope High Resolution Camera data for the Large Magellanic Cloud microlensing event MACHO-LMC-5. By determining the parallax and proper motion of this object we find that the lens is an M dwarf ... More
Quantifiability: Concurrent Correctness from First PrinciplesMay 15 2019Architectural imperatives due to the slowing of Moore's Law, the broad acceptance of relaxed semantics and the O(n!) worst case verification complexity of generating sequential histories motivate a new approach to concurrent correctness. Desiderata for ... More
Estimating sufficient reductions of the predictors in abundant high-dimensional regressionsMay 30 2012We study the asymptotic behavior of a class of methods for sufficient dimension reduction in high-dimension regressions, as the sample size and number of predictors grow in various alignments. It is demonstrated that these methods are consistent in a ... More
Relativized Propositional CalculusMar 09 2012Proof systems for the Relativized Propositional Calculus are defined and compared.
A Vision For Continuous Automated Game DesignJul 30 2017ANGELINA is an automated game design system which has previously been built as a single software block which designs games from start to finish. In this paper we outline a roadmap for the development of a new version of ANGELINA, designed to iterate on ... More
The Connectedness of Space Curve InvariantsJan 28 1994It is a result of Gruson and Peskine that the invariants of a set points in $\ptwo$ in general position are connected. Associated to a space curve there are sequences of invariants which generalize the invariants of points in $\ptwo$. The main result ... More
Maximal Function Inequalities and a Theorem of BirchNov 12 2017Dec 05 2017In this paper we prove an analogue of the discrete spherical maximal theorem of Magyar, Stein, and Wainger, an analogue which concerns maximal functions associated to homogenous algebraic surfaces. Let $\mathfrak{p}$ be a homogenous polynomial in $n$ ... More
Nanoscale changes with low temperature annealing inside composite optical fibresSep 04 2015Nanoscale glass milling with mild thermal annealing is proposed and shown to occur within a tri-material composite W profile optical fibre.
Theory and Techniques for Synthesizing a Family of Graph AlgorithmsJul 04 2012Although Breadth-First Search (BFS) has several advantages over Depth-First Search (DFS) its prohibitive space requirements have meant that algorithm designers often pass it over in favor of DFS. To address this shortcoming, we introduce a theory of Efficient ... More
Step size of the rotary proton motor in single FoF1-ATP synthase from a thermoalkaliphilic bacterium by DCO-ALEX FRETFeb 05 2012Thermophilic enzymes can operate at higher temperatures but show reduced activities at room temperature. They are in general more stable during preparation and, accordingly, are considered to be more rigid in structure. Crystallization is often easier ... More
Galactic Bulge Microlensing Events from the MACHO CollaborationOct 13 2004We present a catalog of 450 high signal-to-noise microlensing events observed by the MACHO collaboration between 1993 and 1999. The events are distributed throughout our fields and, as expected, they show clear concentration toward the Galactic center. ... More
Superhumps and flickering in V1316 CygniOct 08 2007We present analysis and results of a coordinated CCD photometry campaign to observe the 2006 June superoutburst of the cataclysmic variable V1316 Cyg involving 8 longitudinally-distributed observers. The outburst peaked at magnitude 15.03 on June 10, ... 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
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
Elagage d'un perceptron multicouches : utilisation de l'analyse de la variance de la sensibilité des paramètresDec 04 2008The stucture determination of a neural network for the modelisation of a system remain the core of the problem. Within this framework, we propose a pruning algorithm of the network based on the use of the analysis of the sensitivity of the variance of ... More
Infinite reduced words and the Tits boundary of a Coxeter groupJan 05 2013Sep 18 2014Let (W,S) be a finite rank Coxeter system with W infinite. We prove that the limit weak order on the blocks of infinite reduced words of W is encoded by the topology of the Tits boundary of the Davis complex X of W. We consider many special cases, including ... 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
Analysis of Nb3Sn surface layers for superconducting RF cavity applicationsMar 11 2015We present an analysis of the Nb3Sn surface layers grown on a bulk niobium (Nb) coupon prepared at the same time and by the same vapor diffusion process used to make Nb3Sn coatings on 1.3 GHz cavities. Tunneling spectroscopy reveals a well-developed, ... More
The Synoptic All-Sky Infrared (SASIR) SurveyMay 13 2009Jul 31 2009We are proposing to conduct a multicolor, synoptic infrared (IR) imaging survey of the Northern sky with a new, dedicated 6.5-meter telescope at San Pedro M\'artir (SPM) Observatory. This initiative is being developed in partnership with astronomy institutions ... More
SPIRITS: Uncovering Unusual Infrared Transients With SpitzerJan 04 2017We present an ongoing, systematic search for extragalactic infrared transients, dubbed SPIRITS --- SPitzer InfraRed Intensive Transients Survey. In the first year, using Spitzer/IRAC, we searched 190 nearby galaxies with cadence baselines of one month ... More
Investigation of Feshbach Resonances in ultra-cold 40 K spin mixturesJan 09 2017Magnetically-tunable Feshbach resonances are an indispensable tool for experiments with atomic quantum gases. We report on twenty thus far unpublished Feshbach resonances and twenty one further probable Feshbach resonances in spin mixtures of ultracold ... More
Individual band with higher Chern numbers in double perovskite {001} monolayersAug 09 2016Aug 28 2016We show a tight-binding model for double perovskite monolayers grown in the {001} crystallographic direction can exhibit higher Chern numbers for the lowest band of the model dispersion in the absence of an applied magnetic field, including $\pm2$, $\pm4$, ... More
Initial Data for Numerical RelativityJul 31 2000Initial data are the starting point for any numerical simulation. In the case of numerical relativity, Einstein's equations constrain our choices of these initial data. We will examine several of the formalisms used for specifying Cauchy initial data ... More
Bieri-Eckmann Criteria for Profinite GroupsDec 04 2014Jan 15 2015In this paper we derive necessary and sufficient homological and cohomological conditions for profinite groups and modules to be of type $\operatorname{FP}_n$ over a profinite ring $R$, analogous to the Bieri-Eckmann criteria for abstract groups. We use ... More
Continuous Measurement and Stochastic Methods in Quantum Optical SystemsJan 25 2013This dissertation studies the statistics and modeling of a quantum system probed by a coherent laser field. We focus on an ensemble of qubits dispersively coupled to a traveling wave light field. The first research topic explores the quantum measurement ... More
Fisher Lecture: Dimension Reduction in RegressionAug 28 2007Beginning with a discussion of R. A. Fisher's early written remarks that relate to dimension reduction, this article revisits principal components as a reductive method in regression, develops several model-based extensions and ends with descriptions ... More
Majorana Fermions in Proximity-coupled Topological Insulator NanowiresMay 09 2011Nov 08 2011A topological insulator nanowire, proximity-coupled to an ordinary bulk s-wave superconductor and subject to a longitudinal applied magnetic field, is shown to realize a one-dimensional topological superconductor with unpaired Majorana fermions localized ... More
Infrared Period-Luminosity Relations of Evolved Variable Stars in the Large Magellanic CloudJul 28 2010We combine variability information from the MAssive Compact Halo Objects (MACHO) survey of the Large Magellanic Cloud (LMC) with infrared photometry from the Spitzer Space Telescope Surveying the Agents of a Galaxy's Evolution (SAGE) survey to create ... More
Study of the preheating phase of chaotic inflationJan 04 2008Oct 14 2008Particle production and its effects on the inflaton field are investigated during the preheating phase of chaotic inflation using a model consisting of a massive scalar inflaton field coupled to N massless quantum scalar fields. The effects of spacetime ... More
Discovery of Five New R Coronae Borealis Stars in the MACHO Galactic Bulge DatabaseJul 22 2005Sep 21 2005We have identified five new R Coronae Borealis (RCB) stars in the Galactic bulge using the MACHO Project photometry database, raising the total number of known Galactic RCB stars to about 40. We have obtained spectra to confirm the identifications. The ... More
Low-Velocity Impacts on PVDF Targets Using a Light Gas GunOct 19 2010Orbital debris is a constraint on the long-term health of any spacecraft and must be consi-dered during mission planning. Varying mechanisms have been proposed to quantify the problem. Accurate in-situ data is essential with various types of sensors designed ... More
Ordinal analysis of intuitionistic power and exponentiation Kripke Platek set theoryMar 10 2016Until the 1970s, proof theoretic investigations were mainly concerned with theories of inductive definitions, subsystems of analysis and finite type systems. With the pioneering work of Gerhard Jaeger in the late 1970s and early 1980s, the focus switched ... More
Diophantine equations in the primesDec 21 2013Let $\mathfrak{p}=(\mathfrak{p}_1,...,\mathfrak{p}_r)$ be a system of $r$ polynomials with integer coefficients of degree $d$ in $n$ variables $\mathbf{x}=(x_1,...,x_n)$. For a given $r$-tuple of integers, say $\mathbf{s}$, a general local to global type ... More
Adaptive Matching Of The IOTA Ring Linear Optics For Space Charge CompensationMay 07 2018Many present and future accelerators must operate with high intensity beams when distortions induced by space charge forces are among major limiting factors. Betatron tune depression of above approximately 0.1 per cell leads to significant distortions ... More
Fabrication of glucose biosensors by inkjet printingJul 05 2012Inkjet printing has been used to fabricate glucose sensors using glucose oxidase and screen printed carbon electrodes. By appropriate selection of printing and drying conditions we are able to fabricate sensor structures that show a good linear response ... More
Prediction of Silicate Glasses' Stiffness by High-Throughput Molecular Dynamics Simulations and Machine LearningJan 27 2019The development by machine learning of models predicting materials' properties usually requires the use of a large number of consistent data for training. However, quality experimental datasets are not always available or self-consistent. Here, as an ... More
A Note on Homology over Functor CategoriesDec 03 2014It is known that, for $C$ an abelian category and $I$ small, the functor category $C^I$ is again abelian; thus we can do homology in such categories, and examine how it relates to homology in $C$ itself. However, there does not seem to be any good reference ... More
Rejoinder: Fisher Lecture: Dimension Reduction in RegressionAug 28 2007Rejoinder: Fisher Lecture: Dimension Reduction in Regression [arXiv:0708.3774]
Computing over the Reals: Foundations for Scientific ComputingSep 14 2005We give a detailed treatment of the ``bit-model'' of computability and complexity of real functions and subsets of R^n, and argue that this is a good way to formalize many problems of scientific computation. In the introduction we also discuss the alternative ... More
Random billiards with wall temperature and associated Markov chainsFeb 10 2012By a random billiard we mean a billiard system in which the standard specular reflection rule is replaced with a Markov transition probabilities operator P that, at each collision of the billiard particle with the boundary of the billiard domain, gives ... More
Power Law Distribution of the Frequency of Demises of U.S FirmsDec 09 2002Both theoretical and applied economics have a great deal to say about many aspects of the firm, but the literature on the extinctions, or demises, of firms is very sparse. We use a publicly available data base covering some 6 million firms in the US and ... More
Classifying the provably total set functions of KP and KP(P)Oct 07 2016This article is concerned with classifying the provably total set-functions of Kripke-Platek set theory, KP, and Power Kripke-Platek set theory, KP(P), as well as proving several (partial) conservativity results. The main technical tool used in this paper ... More
Constellations in P^dOct 27 2010Nov 12 2010Let A be a subset of positive relative upper density of P^d, the d-tuples of primes. We prove that A contains an affine copy of any finite set of lattice points E, as long as E is in general position in the sense that it has at most one point on every ... More
A Theory For Particle Settling and Shear-Induced Migration in Thin Film FlowOct 16 2007Experiments of particle-laden inclined film flow [Zhou, Dupuy, Bertozzi, and Hosoi, Phys. Rev. Lett. 94 (2005)] have displayed different settling behaviors depending on the particle concentration $\phi$ and angle of inclination $\theta$, in which particles ... More
Theories for TC0 and Other Small Complexity ClassesMay 05 2005Mar 08 2006We present a general method for introducing finitely axiomatizable "minimal" two-sorted theories for various subclasses of P (problems solvable in polynomial time). The two sorts are natural numbers and finite sets of natural numbers. The latter are essentially ... More
Discrepancy properties for random regular digraphsOct 21 2014Oct 26 2015For the uniform random regular directed graph we prove concentration inequalities for (1) codegrees and (2) the number of edges passing from one set of vertices to another. As a consequence, we can deduce discrepancy properties for the distribution of ... More
Homotopical Algebra in Categories with Enough ProjectivesMar 02 2017Mar 06 2018For a complete and cocomplete category $\mathcal{C}$ with a well-behaved class of `projectives' $\bar{\mathcal{P}}$, we construct a model structure on the category $s\mathcal{C}$ of simplicial objects in $\mathcal{C}$ where the weak equivalences, fibrations ... More
Gravitational Space DilationFeb 17 2009We point out that, if one accepts the view that the standard second on an atomic clock is dilated at low gravitational potential (ordinary gravitational time dilation), then the standard meter must also be dilated at low gravitational potential and by ... More
The strength of replacement in weak arithmeticSep 08 2004The replacement (or collection or choice) axiom scheme asserts bounded quantifier exchange. We prove the independence of this scheme from various weak theories of arithmetic, sometimes under a complexity assumption.
Lower bounds for the smallest singular value of structured random matricesAug 26 2016Sep 18 2016We obtain lower tail estimates for the smallest singular value of random matrices with independent but non-identically distributed entries. Specifically, we consider $n\times n$ matrices with complex entries of the form \[ M = A\circ X + B = (a_{ij}\xi_{ij} ... More
Lower bounds for the smallest singular value of structured random matricesAug 26 2016Dec 01 2016We obtain lower tail estimates for the smallest singular value of random matrices with independent but non-identically distributed entries. Specifically, we consider $n\times n$ matrices with complex entries of the form \[ M = A\circ X + B = (a_{ij}\xi_{ij} ... More
The Inherent Geometry of the Nuclear HamiltonianJan 22 2011The symmetries inherent to the nuclear version of the Schr\"odinger wave-equation are identical to the symmetries of a face-centered cubic lattice, as already noted by Wigner in 1937 in the initial development of the independent-particle model (IPM) of ... More
The circular law for signed random regular digraphsAug 02 2015We consider a large random matrix of the form $Y=A\odot X$, where $A$ the adjacency matrix of a uniform random $d$-regular directed graph on $n$ vertices, with $d=\lfloor p n\rfloor$ for some fixed $p \in (0,1)$, and $X$ is an $n\times n$ matrix of iid ... More
On restricted arithmetic progressions over finite fieldsNov 24 2010Nov 29 2010Let A be a subset of $\F_p^n$, the $n$-dimensional linear space over the prime field $\F_p$ of size at least $\de N$ $(N=p^n)$, and let $S_v=P^{-1}(v)$ be the level set of a homogeneous polynomial map $P:\F_p^n\to\F_p^R$ of degree $d$, and $v\in\F_p^R$. ... More
Review of Solid-State ModulatorsAug 19 2000Solid-state modulators for pulsed power applications have been a goal since the first fast high-power semiconductor devices became available. Recent improvements in both the speed and peak power capabilities of semiconductor devices developed for the ... More