Results for "David Cushing"

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The additive structure of the squares inside ringsNov 04 2016When defining the amount of additive structure on a set it is often convenient to consider certain sumsets; Calculating the cardinality of these sumsets can elucidate the set's underlying structure. We begin by investigating finite sets of perfect squares ... More
Ricci-flat cubic graphs with girth fiveFeb 08 2018We classify all connected, simple, 3-regular graphs with girth at least 5 that are Ricci-flat. We use the definition of Ricci curvature on graphs given in Lin-Lu-Yau, Tohoku Math., 2011, which is a variation of Ollivier, J. Funct. Anal., 2009. A graph ... More
Projectivity of Banach and $C^*$-algebras of continuous fieldsApr 26 2011We give necessary and sufficient conditions for the left projectivity and biprojectivity of Banach algebras defined by locally trivial continuous fields of Banach algebras. We identify projective $C^*$-algebras $\A$ defined by locally trivial continuous ... More
Powerful numbers and the ABC-conjectureNov 03 2016The $abc$ conjecture is a very deep concept in number theory with wide application to many areas of number theory. In this article we introduce the conjecture and give examples of its applications. In particular we apply the $abc$ conjecture to the location ... More
Bakry-Émery curvature functions of graphsJun 05 2016We study the Bakry-\'Emery curvature function $\mathcal{K}_{G,x}:(0,\infty]\to \mathbb{R}$ of a vertex $x$ in a locally finite graph $G$ systematically. Here $\mathcal{K}_{G,x}(\mathcal{N})$ is defined as the optimal curvature lower bound $\mathcal{K}$ ... More
Free functions with symmetrySep 05 2014In 1936, Margarete C. Wolf showed that the ring of symmetric free polynomials in two or more variables is isomorphic to the ring of free polynomials in infinitely many variables. We show that Wolf's theorem is a special case of a general theory of the ... More
The Benchmark Ultracool Subdwarf HD 114762B: A Test of Low-Metallicity Atmospheric and Evolutionary ModelsOct 08 2009We present a near-infrared spectroscopic study of HD 114762B, the latest-type metal-poor companion discovered to date and the only ultracool subdwarf with a known metallicity, inferred from the primary star to be [Fe/H] = -0.7. We obtained a medium-resolution ... More
Learning Probabilistic Hierarchical Task Networks to Capture User PreferencesJun 02 2010We propose automatically learning probabilistic Hierarchical Task Networks (pHTNs) in order to capture a user's preferences on plans, by observing only the user's behavior. HTNs are a common choice of representation for a variety of purposes in planning, ... More
Photometric Monitoring of the Coldest Known Brown Dwarf with the Spitzer Space TelescopeSep 19 2016Sep 20 2016Because WISE J085510.83$-$071442.5 (hereafter WISE 0855-0714) is the coldest known brown dwarf ($\sim250$ K) and one of the Sun's closest neighbors (2.2 pc), it offers a unique opportunity for studying a planet-like atmosphere in an unexplored regime ... More
Studying the Physical Diversity of Late-M Dwarfs with Dynamical MassesJul 23 2010We present a systematic study of the physical properties of late-M dwarfs based on high-quality dynamical mass measurements and near-infrared (NIR) spectra. We use astrometry from Keck NGS and LGS AO imaging to determine orbits for late-M binaries. We ... More
Near-Infrared Spectroscopy of the Extrasolar Planet HR 8799 bAug 26 2010[Abridged] We present 2.12-2.23 um high contrast integral field spectroscopy of the extrasolar planet HR 8799 b. Our observations were obtained with OSIRIS on the Keck II telescope and sample the 2.2 um CH4 feature, which is useful for spectral classification ... More
The 0.8-14.5 micron Spectra of Mid-L to Mid-T Dwarfs: Diagnostics of Effective Temperature, Grain Sedimentation, Gas Transport, and Surface GravityJun 16 2009We present new 5.2-14.5 micron low-resolution spectra of 14 mid-L to mid-T dwarfs, as well as 3.0-4.1 micron spectra for five of these dwarfs. These data are supplemented by existing red and near-infrared spectra (0.6-2.5 micron), as well as red through ... More
Near-infrared Thermal Emission Detections of a number of hot Jupiters and the Systematics of Ground-based Near-infrared PhotometryOct 16 2014We present detections of the near-infrared thermal emission of three hot Jupiters and one brown-dwarf using the Wide-field Infrared Camera (WIRCam) on the Canada-France-Hawaii Telescope (CFHT). These include Ks-band secondary eclipse detections of the ... More
The Schizophrenic Spectrum of LSR 1610-0040: a Peculiar M Dwarf/SubdwarfNov 14 2005We present a moderate resolution (R=2000), 0.8-4.1 micron spectrum of LSR 1610-0040, a high proper motion star classified as an early-type L subdwarf by Lepine and collaborators based on its red-optical spectrum. The near-infrared spectrum of LSR 1610-0040 ... More
A Candidate Dual AGN at z=1.175Sep 15 2011The X-ray source CXOXBJ142607.6+353351 (CXOJ1426+35), which was identified in a 172 ks Chandra image in the Bootes field, shows double-peaked rest-frame optical/UV emission lines, separated by 0.69" (5.5 kpc) in the spatial dimension and by 690 km s^-1 ... More
An Infrared High Proper Motion Survey Using 2MASS and SDSS: Discovery of M, L and T DwarfsSep 03 2008Oct 17 2008A search of the Two Micron All Sky Survey and Sloan Digital Sky Survey reveals 36 previously unknown high proper motion objects with J<17. Their red-optical colors indicate that 27 are M dwarfs, 8 are early-type L dwarfs, and 1 is a late-type T dwarf. ... More
WISE Y Dwarfs As Probes of the Brown Dwarf-Exoplanet ConnectionJan 06 2014Feb 09 2014We have determined astrometric positions for 15 WISE-discovered late-type brown dwarfs (6 T8-9 and 9 Y dwarfs) using the Keck II telescope, the Spitzer Space Telescope, and the Hubble Space Telescope. Combining data from 8 to 20 epochs we derive parallactic ... More
Cost Based Satisficing Search Considered HarmfulMar 18 2011Recently, several researchers have found that cost-based satisficing search with A* often runs into problems. Although some "work arounds" have been proposed to ameliorate the problem, there has not been any concerted effort to pinpoint its origin. In ... More
2MASS 22344161+4041387AB: A Wide, Young, Accreting, Low-mass Binary in the LkHa233 GroupFeb 27 2009We report the discovery of a young, 0.16" binary, 2M2234+4041AB, found as the result of a Keck laser guide star adaptive optics imaging survey of young field ultracool dwarfs. Spatially resolved near-infrared photometry and spectroscopy indicate that ... More
HN Peg B: A Test of Models of the L to T Dwarf TransitionApr 09 2008Luhman and collaborators recently discovered an early-T dwarf companion to the G0 dwarf star HN Peg, using Spitzer Infrared Array Camera (IRAC) images. Companionship was established on the basis of the common proper motion inferred from 1998 Two Micron ... More
The L to T Dwarf TransitionSep 10 2004While the precise mechanism responsible for the L to T dwarf transition remains unclear, it is clearly caused by changing cloud characteristics. Here we briefly review data relevant to understanding the nature of the transition and argue that changing ... More
Non-Linearity Corrections and Statistical Uncertainties Associated with Near-Infrared ArraysJan 20 2004We derive general equations for non-linearity corrections and statistical uncertainty (variance) estimates for data acquired with near-infrared detectors employing correlated double sampling, multiple correlated double sampling (Fowler sampling) and uniformly-spaced ... More
The Infrared Telescope Facility (IRTF) Spectral Library: Cool StarsSep 04 2009We present a 0.8 -5 micron spectral library of 210 cool stars observed at a resolving power of R = lambda / Delta lambda ~ 2000 with the medium-resolution infrared spectrograph, SpeX, at the 3.0 m NASA Infrared Telescope Facility (IRTF) on Mauna Kea, ... More
A Method of Correcting Near-Infrared Spectra for Telluric AbsorptionNov 12 2002We present a method for correcting near-infrared medium-resolution spectra for telluric absorption. The method makes use of a spectrum of an A0V star, observed near in time and close in airmass to the target object, and a high-resolution model of Vega, ... More
SDSS J141624.08+134826.7: Blue L Dwarfs and Non-Equilibrium ChemistrySep 14 2010We present an analysis of the recently discovered blue L dwarf SDSS J141624.08+134826.7. We extend the spectral coverage of its published spectrum to ~4 microns by obtaining a low-resolution L band spectrum with SpeX on the NASA IRTF. The spectrum exhibits ... More
Ultracool Dwarf Science from Widefield Multi-Epoch SurveysDec 07 2010Widefield surveys have always provided a rich hunting ground for the coolest stars and brown dwarfs. The single epoch surveys at the beginning of this century greatly expanded the parameter space for ultracool dwarfs. Here we outline the science possible ... More
Characterizing Young Brown Dwarfs using Low Resolution Near-IR SpectraNov 13 2006Nov 15 2006We present near-infrared (1.0-2.4 micron) spectra confirming the youth and cool effective temperatures of 6 brown dwarfs and low mass stars with circumstellar disks toward the Chamaeleon II and Ophiuchus star forming regions. The spectrum of one of our ... More
Surrogate Search As a Way to Combat Harmful Effects of Ill-behaved Evaluation FunctionsNov 01 2014Recently, several researchers have found that cost-based satisficing search with A* often runs into problems. Although some "work arounds" have been proposed to ameliorate the problem, there has been little concerted effort to pinpoint its origin. In ... More
The Exemplar T8 Subdwarf Companion of Wolf 1130Sep 05 2013Oct 01 2013We have discovered a wide separation (188.5") T8 subdwarf companion to the sdM1.5+WD binary Wolf 1130. Companionship of WISE J200520.38+542433.9 is verified through common proper motion over a ~3 year baseline. Wolf 1130 is located 15.83 +/- 0.96 parsecs ... More
An Infrared Spectroscopic Sequence of M, L and T DwarfsDec 13 2004We present a 0.6-4.1 micron spectroscopic sequence of M, L, and T dwarfs. The spectra have R~2000 from 0.9 to 2.4 microns and R=2500-200 from 2.9 to 4.1 microns. These new data nearly double the number of L and T dwarfs that have reported L-band spectra. ... More
Near-Infrared Spectroscopy of McNeil's Nebula ObjectMay 24 2004We present 0.8-5.2 micron spectroscopy of the compact source at the base of a variable nebula (McNeil's Nebula Object) in the Lynds 1630 dark cloud that went into outburst in late 2003. The spectrum of this object reveals an extremely red continuum, CO ... More
A Spitzer Infrared Spectrograph (IRS) Spectral Sequence of M, L, and T DwarfsMay 24 2006We present a low-resolution (R = 90), 5.5-38 micron spectral sequence of a sample of M, L, and T dwarfs obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. The spectra exhibit prominent absorption bands of H_2O at 6.27 microns, ... More
Trigonometric Parallaxes for Two Late-Type Subdwarfs: LSR1425+71 (sdM8.0) and the Binary LSR1610-00 (sd?M6pec)Jun 13 2008Trigonometric parallax astrometry and BVI photometry are presented for two late-type subdwarf candidates, LSR1425+71 (sdM8.0) and LSR1610-00 (sd?M6pec). For the former we measure an absolute parallax of 13.37+/-0.51 mas yielding Mv=15.25+/-0.09. The astrometry ... More
Stable Leader Election in Population Protocols Requires Linear TimeFeb 14 2015Aug 20 2016A population protocol *stably elects a leader* if, for all $n$, starting from an initial configuration with $n$ agents each in an identical state, with probability 1 it reaches a configuration $\mathbf{y}$ that is correct (exactly one agent is in a special ... More
The transverse proximity effect in the z ~ 2 Lyman-alpha forest suggests QSO episodic lifetimes of ~1 MyrSep 12 2008We look for signs of the H~I transverse proximity effect in the spectra of 130 QSO pairs, most with transverse separations in the plane of the sky of 0.1 -- 3 Mpc at z ~ 2.2. We expected to see a decrease in Lyman-alpha forest HI absorption in the spectrum ... More
Comet Encounters and Carbon 14Nov 26 2012The $^{14}$C production of shock-accelerated particles is calculated in terms of the total energy released in energetic particles. The recently reported 1.2% jump in the $^{14}$C content of the atmosphere in the year C.E. 775, it is found, would require ... More
The Detection of Two Distinct High Ionization States in a QSO Lyman Limit Absorption System: Evidence for Hierarchical Galaxy Formation at z ~ 3?Jan 19 1999We have detected two high ionization phases of gas in the z ~ 2.77 partial Lyman limit system (LLS) towards QSO 1157-3143. We detect the first phase by CIV and SiIV absorption, and the second phase -- which is either warmer or undergoing larger random ... More
Continuum Percolation for Quermass ModelJan 11 2012The continuum percolation for Markov (or Gibbs) germ-grain models is investigated. The grains are assumed circular with random radii on a compact support. The morphological interaction is the so-called Quermass interaction defined by a linear combination ... More
Randomized greedy algorithms for independent sets and matchings in regular graphs: Exact results and finite girth correctionsJul 08 2008We derive new results for the performance of a simple greedy algorithm for finding large independent sets and matchings in constant degree regular graphs. We show that for $r$-regular graphs with $n$ nodes and girth at least $g$, the algorithm finds an ... More
Results for the LISA Phase Measurement System ProjectNov 01 2004Jan 11 2005This article presents some of the more topical results of a study into the LISA phase measurement system. This system is responsible for measuring the phase of the heterodyne signal caused by the interference of the laser beams between the local and far ... More
The RASNIK Real-Time Relative Alignment Monitor for the CDF Inner Tracking DetectorsDec 10 2002We describe the design and operation of the RASNIK optical relative alignment system designed for and installed on the CDF inner tracking detectors. The system provides low-cost minute-by-minute alignment monitoring with submicron precision. To reduce ... More
A Katznelson-Tzafriri theorem for measuresOct 06 2014This article generalises the well-known Katznelson-Tzafriri theorem for a $C_0$-semigroup $T$ on a Banach space $X$, by removing the assumption that a certain measure in the original result be absolutely continuous. In an important special case the rate ... More
Strategies for The Determination of phi3 in B- -> D0 K-Mar 30 2001Direct CP violation in decays such as B- -> D0 K- is sensitive to the CKM angle phi_3 because these decays allow the interference of b-quark to c-quark with b-quark to u-quark transitions. Indeed, phi_3 may be determined if one can infer the strong phase ... More
Digit permutations revisitedMay 12 2016We discuss here characteristic $p$ $L$-series as well as the group $S_{(q)}$ which appears to act as symmetries of these functions. We explain various actions of $S_{(q)}$ that arise naturally in the theory as well as extensions of these actions. In general ... More
Equations of Riemann surfaces with automorphismsJul 16 2016We present an algorithm for computing equations of canonically embedded Riemann surfaces with automorphisms. A variant of this algorithm with many heuristic improvements is used to produce equations of Riemann surfaces $X$ with large automorphism groups ... More
Submersions and effective descent of etale morphismsOct 12 2007Mar 05 2010Using the flatification by blow-up result of Raynaud and Gruson, we obtain new results for submersive and subtrusive morphisms. We show that universally subtrusive morphisms, and in particular universally open morphisms, are morphisms of effective descent ... More
Information as Distinctions: New Foundations for Information TheoryJan 23 2013Jan 26 2013The logical basis for information theory is the newly developed logic of partitions that is dual to the usual Boolean logic of subsets. The key concept is a "distinction" of a partition, an ordered pair of elements in distinct blocks of the partition. ... More
A Direct Proof of BCFW Recursion for Twistor-StringsJul 01 2010This paper gives a direct proof that the leading trace part of the genus zero twistor-string path integral obeys the BCFW recursion relation. This is the first complete proof that the twistor-string correctly computes all tree amplitudes in maximally ... More
On Green's functions for positive, self-adjoint, elliptic pseudo-differential operators on closed, Riemannian manifoldsMar 30 2010Jun 21 2011In this short note we review some facts about elliptic differential operators on Riemannian manifolds.
The eigenvectors of the right-justified Pascal triangleNov 13 2000We find the eigenvalues and eigenvectors of the n by n matrix with (i,j) entry \binom(i-1,n-j), establishing a conjecture of Peele and Stanica. Curiously, the eigenvectors can be chosen to form a matrix which is its own inverse.
Encoding !-tensors as !-graphs with neighbourhood ordersNov 05 2015Diagrammatic reasoning using string diagrams provides an intuitive language for reasoning about morphisms in a symmetric monoidal category. To allow working with infinite families of string diagrams, !-graphs were introduced as a method to mark repeated ... More
Spectral expansion of Schwartz linear operatorsApr 19 2011May 29 2011In this paper we prove and apply a theorem of spectral expansion for Schwartz linear operators which have an S-linearly independent Schwartz eigenfamily. This type of spectral expansion is the analogous of the spectral expansion for self-adjoint operators ... More
Internally heated convection beneath a poor conductorJun 29 2016We consider convection in an internally heated layer of fluid that is bounded below by a perfect insulator and above by a poor conductor. The poorly conducting boundary is modelled by a fixed heat flux. Using solely analytical methods, we find linear ... More
A Quantum Hall Fluid of VorticesJun 26 2003Jul 03 2003In this note we demonstrate that vortices in a non-relativistic Chern-Simons theory form a quantum Hall fluid. We show that the vortex dynamics is controlled by the matrix mechanics previously proposed by Polychronakos as a description of the quantum ... More
The Moduli Space of BPS Domain WallsFeb 01 2002Apr 25 2002N=2 SQED with several flavors admits multiple, static BPS domain wall solutions. We determine the explicit two-kink metric and examine the dynamics of colliding domain walls. The multi-kink metric has a toric Kahler structure and we reduce the Kahler ... More
The Holographic Dual of AdS3 x S3 x S3 x S1Feb 20 2014Jan 20 2016We construct the two dimensional N=(0,4) gauge theory that lives on the world volume of D1-branes and intersecting D5-branes. We conjecture that this theory flows in the infra-red to a fixed point with large N=(4,4) superconformal symmetry. The central ... More
Superconformal Vortex StringsOct 19 2006Nov 27 2006We study the low-energy dynamics of semi-classical vortex strings living above Argyres-Douglas superconformal field theories. The worldsheet theory of the string is shown to be a deformation of the CP^N model which flows in the infra-red to a superconformal ... More
Classicality of quantum information processingAug 22 2001May 01 2002The ultimate goal of the classicality programme is to quantify the amount of quantumness of certain processes. Here, classicality is studied for a restricted type of process: quantum information processing (QIP). Under special conditions, one can force ... More
Constructing local L-packets for tame unitary groupsNov 29 2013We generalize the work of DeBacker and Reeder to the case of unitary groups split by a tame extension. The approach is broadly similar and the restrictions on the parameter the same, but many of the details of the arguments differ. Let $G$ be a unitary ... More
Non-commutative vs. Commutative Descriptions of D-brane BIonsFeb 02 2000Feb 09 2000The U(1) gauge theory on a D3-brane with non-commutative worldvolume is shown to admit BIon-like solutions which saturate a BPS bound on the energy. The mapping of these solutions to ordinary fields is found exactly, namely non-perturbatively in the non-commutativity ... More
Developing and Analyzing Boundary Detection Operators Using Probabilistic ModelsMar 27 2013Most feature detectors such as edge detectors or circle finders are statistical, in the sense that they decide at each point in an image about the presence of a feature, this paper describes the use of Bayesian feature detectors.
On the Ramsey multiplicity of complete graphsNov 30 2007We show that, for $n$ large, there must exist at least \[\frac{n^t}{C^{(1+o(1))t^2}}\] monochromatic $K_t$s in any two-colouring of the edges of $K_n$, where $C \approx 2.18$ is an explicitly defined constant. The old lower bound, due to Erd\H{o}s \cite{E62}, ... More
Graphs with few paths of prescribed length between any two verticesNov 04 2014We use a variant of Bukh's random algebraic method to show that for every natural number $k \geq 2$ there exists a natural number $\ell$ such that, for every $n$, there is a graph with $n$ vertices and $\Omega_k(n^{1 + 1/k})$ edges with at most $\ell$ ... More
Combinatorial theorems relative to a random setApr 12 2014May 22 2014We describe recent advances in the study of random analogues of combinatorial theorems.
Mapping R&D support infrastructures: A scientometric and webometric study of UK science parksJul 27 2014This thesis analyses UK SPs with an informetric approach to study (1) the role of public science and HEIs in research and development (R&D) networks associated with SPs, and (2) the web-based patterns that reflect the configuration of R&D support infrastructures ... More
In-plane conductivity of a layered large-bipolaron liquidAug 08 2014Jan 13 2015Distinctive normal-state properties of cuprate superconductors follow from their charge carriers forming a large-bipolaron liquid. The very weak scattering of the slow-moving heavy-massed excitations of the liquid by acoustic phonons yields a scattering ... More
Duality Invariance of Cosmological Perturbation SpectraSep 22 1998Apr 21 1999I show that cosmological perturbation spectra produced from quantum fluctuations in massless or self-interacting scalar fields during an inflationary era remain invariant under a two parameter family of transformations of the homogeneous background fields. ... More
Counting Rational Points on K3 SurfacesMar 02 1999Mar 04 1999For any algebraic variety $V$ defined over a number field $k$, and ample height function $H$ on $V$, one can define the counting function $N_V(B) = #{P\in V(k) \mid H(P)\leq B}$. In this paper, we calculate the counting function for Kummer surfaces $V$ ... More
Do parton cascade model results approach chemical equilibrium?Mar 03 1994Apr 05 1994This comment is withdrawn, as the figure on which it was based is inconsistent with other figures in the text and thus probably incorrect. Using the other figures, I find that the parton cascade model does approach chemical equilibrium correctly.
Edge Cover Colouring Versus Minimum Degree in MultigraphsJun 09 2009Jul 22 2010An edge colouring of a multigraph can be thought of as a partition of the edges into matchings (a matching meets each vertex at most once). Analogously, an edge cover colouring is a partition of the edges into edge covers (an edge cover meets each vertex ... More
An Optimal Distributed Edge-Biconnectivity AlgorithmFeb 05 2006We describe a synchronous distributed algorithm which identifies the edge-biconnected components of a connected network. It requires a leader, and uses messages of size O(log |V|). The main idea is to preorder a BFS spanning tree, and then to efficiently ... More
Estimating a bivariate linear relationshipFeb 05 2012Solutions of the bivariate, linear errors-in-variables estimation problem with unspecified errors are expected to be invariant under interchange and scaling of the coordinates. The appealing model of normally distributed true values and errors is unidentified ... More
Breaking the n^(log n) Barrier for Solvable-Group IsomorphismMay 03 2012Dec 11 2013We consider the group isomorphism problem: given two finite groups G and H specified by their multiplication tables, decide if G and H are isomorphic. The n^(log n) barrier for group isomorphism has withstood all attacks --- even for the special cases ... More
Orbifolds and SolitonsDec 19 1995May 09 1996We propose a conformal field theory description of a solitonic heterotic string in type $IIA$ superstring theory compactified on $K3$, generalizing previous work by J. Harvey, A. Strominger and A. Sen. In ten dimensions the construction gives a fivebrane ... More
Irreversibility of the Renormalization Group Flow in Two Dimensional Quantum GravityJul 20 1992We argue that the torus partition sum in $2d$ (super) gravity, which counts physical states in the theory, is a decreasing function of the renormalization group scale. As an application we chart the space of $(\hat c\leq1)$ $c\leq1$ models coupled to ... More
Studies toward a Candidate IDS Neutrino Factory Front-End ConfigurationJul 17 2012A front end scenario for the IDS neutrino factory is presented. The scenario is based on the Study 2A example for capture, bunching and phase-energy rotation of muons from a proton source for a neutrino factory, and the goal is the capture of a maximal ... More
Eight light flavors on large lattice volumesOct 25 2013Nov 10 2013I present first results from large-scale lattice investigations of SU(3) gauge theory with eight light flavors in the fundamental representation. Using leadership computing resources at Argonne, we are generating gauge configurations with lattice volumes ... More
Semantics, Representations and Grammars for Deep LearningSep 29 2015Deep learning is currently the subject of intensive study. However, fundamental concepts such as representations are not formally defined -- researchers "know them when they see them" -- and there is no common language for describing and analyzing algorithms. ... More
Split Injectivity of the Baum-Connes Assembly MapDec 02 2003In this work, the continuously controlled techniques developed by Carlsson and Pedersen are used to prove that the Baum-Connes map is a split injection for groups satisfying certain geometric conditions.
Pattern avoidance in "flattened" partitionsFeb 15 2008To flatten a set partition (with apologies to Mathematica) means to form a permutation by erasing the dividers between its blocks. Of course, the result depends on how the blocks are listed. For the usual listing--increasing entries in each block and ... More
A determinant of Stirling cycle numbers counts unlabeled acyclic single-source automataMar 31 2007We show that a determinant of Stirling cycle numbers counts unlabeled acyclic single-source automata. The proof involves a bijection from these automata to certain marked lattice paths and a sign-reversing involution to evaluate the determinant.
Permutations avoiding a nonconsecutive instance of a 2- or 3-letter patternOct 13 2006Nov 02 2006We count permutations avoiding a nonconsecutive instance of a two- or three-letter pattern, that is, the pattern may occur but only as consecutive entries in the permutation. Two-letter patterns give rise to the Fibonacci numbers. The counting sequences ... More
Top Quark Physics Results from CDF and D0Sep 18 1996I summarize recent top quark physics results from the Fermilab Tevatron experiments. Since the observation of the top quark by CDF and D0 in 1995, the experimental focus has shifted to a detailed study of the top quark's properties. This article describes ... More
Aspects of Recurrence and Transience for Levy Processes in Transformation Groups and Non-Compact Riemannian Symmetric PairsMar 21 2011We study recurrence and transience for L\'{e}vy processes induced by topological transformation groups. In particular the transience-recurrence dichotomy in terms of potential measures is established and transience is shown to be equivalent to the potential ... More
A State-Transition Grammar for Data-Oriented ParsingFeb 27 1995This paper presents a grammar formalism designed for use in data-oriented approaches to language processing. The formalism is best described as a right-linear indexed grammar extended in linguistically interesting ways. The paper goes on to investigate ... More
Replicating and Applying a Neuro-Cognitive Experimental Technique in HCI ResearchJul 11 2013In cognitive neuroscience the sense of agency is defined as the as the experience of controlling ones own actions and, through this control, affecting the external world. At CHI 2012 I presented a paper entitled I did that! Measuring Users Experience ... More
Testing the Capital Asset Pricing Model (CAPM) on the Uganda Stock ExchangeDec 31 2010This paper examines the validity of the Capital Asset Pricing Model (CAPM) on the Ugandan stock market using monthly stock returns from 10 of the 11 companies listed on the Uganda Stock Exchange (USE), for the period 1st March 2007 to 10th November 2009. ... More
Charges in Gauge TheoriesFeb 28 2007Recent progress in the construction of both electric, coloured and magnetic charges in gauge theories will be presented. The topological properties of the charged sectors will be highlighted as well as the applications of this work to confinement and ... More
A Hausdorff measure version of the Jarník--Schmidt theorem in Diophantine approximationSep 13 2015Sep 02 2016We solve the problem of giving sharp asymptotic bounds on the Hausdorff dimensions of certain sets of badly approximable matrices, thus improving results of Broderick and Kleinbock (preprint 2013) as well as Weil (preprint 2013), and generalizing to higher ... More
Moduli spaces of homotopy theoryOct 05 2004The moduli spaces refered to are topological spaces whose path components parametrize homotopy types. Such objects have been studied in two separate contexts: rational homotopy types, in the work of several authors in the late 1970's; and general homotopy ... More
In Quantum Computing Speedup Illusory?: The False Coin of "Counting Function Evaluations"Jul 16 2014Aug 17 2015By using a new way to encode Boolean functions in a reversible gate, an algorithm is developed in quantum computing over Z_2, symbolized QC/2, (as opposed to QC over C) that needs only one function evaluation to solve the Grover Database Search Problem ... More
Random Substitution-Insertion-Deletion (RSID) Model of Molecular Evolution with Alignment-free Parameter EstimationFeb 09 2011We present a comprehensive new framework for handling biologically accurate models of molecular evolution. This model provides a systematic framework for studying models of molecular evolution that implement heterogeneous rates, conservation of reading ... More
Topological Entropy of DNA SequencesJan 24 2011Topological entropy has been one of the most difficult to implement of all the entropy-theoretic notions. This is primarily due to finite sample effects and high-dimensionality problems. In particular, topological entropy has been implemented in previous ... More
On Self-Predicative Universals in Category TheoryMay 09 2014May 11 20151. This paper shows how the universals of category theory in mathematics provide a model (in the Platonic Heaven of mathematics) for the self-predicative strand of Plato's Theory of Forms as well as for the idea of a "concrete universal" in Hegel and ... More
Searching for Hydrogen in Type Ib Supernovae, and for Helium and Hydrogen in Type IcJul 09 2002Identifying the progenitors of Type Ib and Type Ic supernovae requires knowing, among other things, whether SNe Ib eject hydrogen, and whether SNe Ic eject helium, and perhaps even hydrogen. Recently it has become clear that some SNe Ib do eject hydrogen, ... More
On quasiconformal selfmappings of the unit disk and elliptic PDE in the planeSep 06 2010Feb 18 2012We prove the following theorem: if $w$ is a quasiconformal mapping of the unit disk onto itself satisfying elliptic partial differential inequality $|L[w]|\le \mathcal{B}|\nabla w|^2+\Gamma$, then $w$ is Lipschitz continuous. This {result} extends some ... More
A proof of Khavinson's conjecture in $\mathbf{R}^4$Jan 13 2016The paper deals with an extremal problem for bounded harmonic functions in the unit ball of $\mathbf{R}^4$. We solve the generalized Khavinson problem in $\mathbf{R}^4$. This precise problem was formulated by G. Kresin and V. Maz'ya for harmonic functions ... More
On J. C. C. Nitsche's type inequality for hyperbolic space $\mathbf{H}^3$Feb 20 2012Feb 21 2012Let $\mathbf H^3$ be the hyperbolic space identified with the unit ball $\mathbf{B}^3 = \{x\in \mathbf{R}^3: |x| < 1\}$ with the Poincar\'e metric $d_h$ and assume that ${\mathcal{A}}(x_0,p,q):=\{x: p<d_h(x,x_0)< q\}\subset \mathbf H^3$ is an hyperbolic ... More
Quasiconformal harmonic mappings between $\,\mathscr C^{1,μ}$ Euclidean surfacesMar 08 2011The conformal deformations are contained in two classes of mappings: quasiconformal and harmonic mappings. In this paper we consider the intersection of these classes. We show that, every $K$ quasiconformal harmonic mapping between $\,\mathscr C^{1,\mu}$ ... More
Cauchy transform and Poisson's equationMar 19 2010Let $u\in W^{2,p}_0$, $1\le p\le \infty$ be a solution of the Poisson equation $\Delta u = h$, $h\in L^p$, in the unit disk. It is proved that $\|\nabla u\|_{L^p} \le a_p\|h\|_{L^p}$ with sharp constant $a_p$ for $p=1$ and $p=\infty$ and that $\|\partial ... More