Results for "Colin Riba"

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A Functional (Monadic) Second-Order Theory of Infinite TreesMar 14 2019This paper presents a complete axiomatization of Monadic Second-Order Logic (MSO) over infinite trees. MSO on infinite trees is a rich system, and its decidability ("Rabin's Tree Theorem") is one of the most powerful known results concerning the decidability ... More
A Curry-Howard Approach to Church's SynthesisMar 23 2018Feb 13 2019Church's synthesis problem asks whether there exists a finite-state stream transducer satisfying a given input-output specification. For specifications written in Monadic Second-Order Logic over infinite words, Church's synthesis can theoretically be ... More
On the confluence of lambda-calculus with conditional rewritingSep 20 2011The confluence of untyped \lambda-calculus with unconditional rewriting is now well un- derstood. In this paper, we investigate the confluence of \lambda-calculus with conditional rewriting and provide general results in two directions. First, when conditional ... More
On the confluence of lambda-calculus with conditional rewritingSep 01 2006Sep 11 2006The confluence of untyped lambda-calculus with unconditional rewriting has already been studied in various directions. In this paper, we investigate the confluence of lambda-calculus with conditional rewriting and provide general results in two directions. ... More
On Learning More Appropriate Selectional RestrictionsFeb 09 1995We present some variations affecting the association measure and thresholding on a technique for learning Selectional Restrictions from on-line corpora. It uses a wide-coverage noun taxonomy and a statistical measure to generalize the appropriate semantic ... More
An Experiment on Learning Appropriate Selectional Restrictions from a Parsed CorpusSep 07 1994We present a methodology to extract Selectional Restrictions at a variable level of abstraction from phrasally analyzed corpora. The method relays in the use of a wide-coverage noun taxonomy and a statistical measure of the co-occurrence of linguistic ... More
Automorphisms of descending mod-p central seriesMar 11 2019Given a free group $\Gamma$ of finite rank $n$ and a prime number $p,$ denote by $\Gamma_k^\bullet$ the $k^\text{th}$ layer of the Stallings ($\bullet=S$) or Zassenhaus ($\bullet=Z$) $p$-central series, by $\mathcal{N}_{k}^\bullet$ the quotient $\Gamma/\Gamma_{k+1}^\bullet$ ... More
A model for ultrarelativistic spherically symmetric Pre-Hawking radiating gravitational collapseApr 30 2012Jun 23 2014In this paper we present a simple but non-simplistic model of gravitational collapse with thermal emission of pre-Hawking radiation. We apply Einstein equations to a time-dependant spherically symmetric metric and an ultrarelativistic stress-energy tensor. ... More
Window-Dependent Bases for Efficient Representations of the Stockwell TransformJun 02 2014Dec 31 2014Since its appearing in 1996, the Stockwell transform (S-transform) has been applied to medical imaging, geophysics and signal processing in general. In this paper, we prove that the system of functions (so-called DOST basis) is indeed an orthonormal basis ... More
Triple Crossing Number of Knots and LinksJul 31 2012Sep 04 2012A triple crossing is a crossing in a projection of a knot or link that has three strands of the knot passing straight through it. A triple crossing projection is a projection such that all of the crossings are triple crossings. We prove that every knot ... More
A new paradigm for the universeNov 03 2003Jan 25 2012A new paradigm for the universe is presented in which the universe is far older than current estimates and there is no big bang.
On 2-powerfully Perfect Numbers in Three Quadratic RingsDec 09 2014Dec 11 2014Using an extension of the abundancy index to imaginary quadratic rings with unique factorization, we define what we call $n$-powerfully perfect numbers in these rings. This definition serves to extend the concept of perfect numbers that have been defined ... More
An Extension of the Abundancy Index to Certain Quadratic RingsJun 17 2015We begin by introducing an extension of the traditional abundancy index to imaginary quadratic rings with unique factorization. After showing that many of the properties of the traditional abundancy index continue to hold in our extended form, we investigate ... More
Unitary Multiperfect Numbers in Certain Quadratic RingsDec 09 2014A unitary divisor $c$ of a positive integer $n$ is a positive divisor of $n$ that is relatively prime to $\displaystyle{\frac{n}{c}}$. For any integer $k$, the function $\sigma_k^*$ is a multiplicative arithmetic function defined so that $\sigma_k^*(n)$ ... More
Observation of M87 with VERITASSep 23 2007The giant radio galaxy M87 is the only extragalactic non-blazar object which has been detected as a source of very high energy gamma-rays. It represents a unique opportunity to study the phenomena of gamma-ray emission from a nearby AGN. In this paper ... More
An introduction to mesic nucleiJan 14 2016There is much speculation and a modest amount of evidence that certain mesons might form quasi-bound states with nuclei to produce really exotic states of matter. For this to be a practical possibility, the interaction between the meson and nucleons at ... More
COSY-11 : How will we remember it ?Sep 03 2007A personal selection is made of the highlights of the COSY-11 physics program undertaken at the COoler SYnchrotron of the Forschungszentrum Juelich. This has been particularly rich in the field of strange and non-strange meson production in proton-proton ... More
On the structure of just infinite profinite groupsJun 09 2009Jun 26 2009A profinite group $G$ is just infinite if every closed normal subgroup of $G$ is of finite index. We prove that an infinite profinite group is just infinite if and only if, for every open subgroup $H$ of $G$, there are only finitely many open normal subgroups ... More
Mony a Mickle Maks a Muckle: Minor Body Observations with Optical Telescopes of All SizesMar 17 2009I review the current capabilities of small, medium and large telescopes in the study of minor bodies of the Solar System (MBOSS), with the goal of identifying those areas where the next generation of Extremely Large Telescopes (ELTs) are required to progress. ... More
Some Poset Pattern-Avoidance Problems Posed by YakoubovAug 13 2016Extending the work of Yakoubov, we enumerate the linear extensions of comb posets that avoid certain length-$3$ patterns. We resolve many of Yakoubov's open problems and prove both of the conjectures from her paper.
Some Poset Pattern-Avoidance Problems Posed by YakoubovAug 13 2016Nov 24 2016Extending the work of Yakoubov, we enumerate the linear extensions of comb posets that avoid certain length-$3$ patterns. We resolve many of Yakoubov's open problems and prove both of the conjectures from her paper.
Enumerating Periodic Points of Certain Sequential Dynamical SystemsNov 22 2015A sequential dynamical system (SDS) consists of an undirected simple graph $Y$ with vertices $v_1,v_2,\ldots,v_n$, a collection of vertex functions $\{f_{v_i}\}_{i=1}^n$, a permutation $\pi\in S_n$, and a collection of states $A$. In this system, vertices ... More
Preimages under the Stack-Sorting AlgorithmNov 18 2015Apr 06 2016We use a method for determining the number of preimages of any permutation under the stack-sorting map in order to obtain recursive upper bounds for the numbers $W_t(n)$ and $W_t(n,k)$ of $t$-stack sortable permutations of length $n$ and $t$-stack sortable ... More
Improved gluonic actions on anisotropic latticesAug 05 1996The use of novel perturbatively-improved gluonic actions on anisotropic lattices in which the temporal spacing is much smaller than that in the spatial directions is discussed. Such actions permit more efficient measurements of noisy correlation functions, ... More
Preimages under the Stack-Sorting AlgorithmNov 18 2015Jun 02 2018We use a method for determining the number of preimages of any permutation under the stack-sorting map in order to obtain recursive upper bounds for the numbers $W_t(n)$ and $W_t(n,k)$ of $t$-stack sortable permutations of length $n$ and $t$-stack sortable ... More
The Harish-Chandra integralJun 28 2018This paper introduces Harish-Chandra's integral formula for compact, connected, semisimple Lie groups. It is intended for mathematicians and physicists who are familiar with the basics of Lie groups and Lie algebras but who may not be specialists in representation ... More
Lens rigidity for manifolds with hyperbolic trapped setDec 04 2014Dec 21 2015For a Riemannian manifold $(M,g)$ with strictly convex boundary $\partial M$, the lens data consists in the set of lengths of geodesics $\gamma$ with endpoints on $\partial M$, together with their endpoints $(x_-,x_+)\in \partial M\times \partial M$ and ... More
Connectivity for bridge-alterable graph classesNov 13 2013Mar 01 2016A collection of graphs is called bridge-alterable if, for each graph G with a bridge e, G is in the class if and only if G-e is. For example the class of forests is bridge-alterable. For a random forest $F_n$ sampled uniformly from the set of forests ... More
Stack-Sorting Preimages of Permutation ClassesSep 10 2018Feb 11 2019We extend and generalize many of the enumerative results concerning West's stack-sorting map $s$. First, we prove a useful theorem that allows one to efficiently compute $|s^{-1}(\pi)|$ for any permutation $\pi$, answering a question of Bousquet-M\'elou. ... More
Postorder PreimagesApr 06 2016Jun 02 2018Given a set $Y$ of decreasing plane trees and a permutation $\pi$, how many trees in $Y$ have $\pi$ as their postorder? Using combinatorial and geometric constructions, we provide a method for answering this question for certain sets $Y$ and all permutations ... More
Deconvolution by simulationAug 08 2007Given samples (x_1,...,x_m) and (z_1,...,z_n) which we believe are independent realizations of random variables X and Z respectively, where we further believe that Z=X+Y with Y independent of X, the problem is to estimate the distribution of Y. We present ... More
Multiperfect Numbers in Certain Quadratic RingsJun 17 2015Using an extension of the abundancy index to imaginary quadratic rings that are unique factorization domains, we investigate what we call $n$-powerfully $t$-perfect numbers in these rings. This definition serves to extend the concept of multiperfect numbers ... More
The large structures of Grothendieck founded on finite order arithmeticFeb 09 2011Apr 30 2014Such large-structure tools of cohomology as toposes and derived categories stay close to arithmetic in practice, yet existing foundations for them go beyond the strong set theory ZFC. We formalize the practical insight by founding the theorems of EGA ... More
Unitary Cayley Graphs of Dedekind Domain QuotientsDec 09 2014If $X$ is a commutative ring with unity, then the unitary Cayley graph of $X$, denoted $G_X$, is defined to be the graph whose vertex set is $X$ and whose edge set is $\{\{a,b\}\colon a-b\in U(X)\}$, where $U(X)$ denotes the group of units of $X$. When ... More
The inhabitance paradox: how habitability and inhabitancy are inseparableMar 03 2016The dominant paradigm in assigning "habitability"' to terrestrial planets is to define a circumstellar habitable zone: the locus of orbital radii in which the planet is neither too hot nor too cold for life as we know it. One dimensional climate models ... More
Subgroups of finite index and the just infinite propertyMay 11 2009A residually finite (profinite) group $G$ is just infinite if every non-trivial (closed) normal subgroup of $G$ is of finite index. This paper considers the problem of determining whether a (closed) subgroup $H$ of a just infinite group is itself just ... More
A Note about Iterated Arithmetic FunctionsJan 24 2015Let $f\colon\mathbb{N}\rightarrow\mathbb{N}_0$ be a multiplicative arithmetic function such that for all primes $p$ and positive integers $\alpha$, $f(p^{\alpha})<p^{\alpha}$ and $f(p)\vert f(p^{\alpha})$. Suppose also that any prime that divides $f(p^{\alpha})$ ... More
Near-Threshold Production of $η$-MesonsJan 11 1993It is shown that the striking energy variation in the $p\, d \rightarrow \mbox{$^{\, 3}{\rm He}$}\, \eta$ cross section near threshold is probably due to a final state interaction associated with a large (complex) $\eta -\mbox{$^{3}{\rm He}$}$ scattering ... More
The Continuing Outburst of V1647~Orionis: Winter/Spring 2011 ObservationsAug 06 2011Aug 10 2011We present optical and near-IR observations of the young eruptive variable star V1647 Orionis which illuminates McNeil's Nebula. In late 2003, V1647 Ori was observed to brightened by around 5 mag to r'=17.7. In early 2006 the star faded back to its quiescent ... More
V2492 Cygni: The Early Evolution of the 2010 OutburstMay 04 2011We present Gemini-North optical and near-IR observations of a young eruptive star in Cygnus, designated as V2492 Cyg in the General Catalog of Variable Stars. This object is one of two young stars, located within 2 degrees of each other, that recently ... More
Forms and Rotational States of the Nuclei of Ecliptic CometsJan 12 2007In this thesis I present measurements of the physical properties of the nuclei of Jupiter Family comets (JFCs), based on time-series observations. From the time-series photometry rotation rates and elongations were measured, and from these constraints ... More
Sub-Compton quantum non-equilibrium and Majorana systemsJun 05 2013We study the Majorana equation from the point of view of the de Broglie-Bohm pilot-wave theory (according to which a quantum ensemble of fermions is not only described by a spinor but also by a distribution of position configurations). Although the Majorana ... More
Absence of resonance near the critical line on asymptotically hyperbolic spacesJun 24 2004Sep 02 2005As a consequence of a result of Cardoso and Vodev, we show that the resolvent of the Laplacian on asymptotically hyperbolic manifolds is analytic in an exponential neighbourhood of the critical line. The case of non-trapping metrics with constant curvature ... More
Waist size for cusps in hyperbolic 3-manifolds IIMar 03 2017The waist size of a cusp in an orientable hyperbolic 3-manifold is the length of the shortest nontrivial curve generated by a parabolic isometry in the maximal cusp boundary. Previously, it was shown that the smallest possible waist size, which is 1, ... More
Cabling Conjecture for Small Bridge NumberJul 06 2015Let $k\subset S^3$ be a nontrivial knot. The Cabling Conjecture of Francisco Gonz\'alez-Acu\~na and Hamish Short posits that $\pi$-Dehn surgery on $k$ produces a reducible manifold if and only if $k$ is a $(p,q)$-cable knot and the surgery slope $\pi$ ... More
Bipyramids and bounds on volumes of hyperbolic linksNov 07 2015We utilize ideal bipyramids to obtain new upper bounds on volume for hyperbolic link complements in terms of the combinatorics of their projections.
Counting 3-Stack-Sortable PermutationsMar 21 2019We prove a "Decomposition Lemma" that allows us to count preimages of certain sets of permutations under West's stack-sorting map $s$. As a first application, we give a new proof of Zeilberger's formula for the number of 2-stack-sortable permutations ... More
The generalised Fitting subgroup of a profinite groupApr 02 2009The generalised Fitting subgroup of a finite group is the group generated by all subnormal subgroups that are either nilpotent or quasisimple. The importance of this subgroup in finite group theory stems from the fact that it always contains its own centraliser, ... More
Hyperbolic KnotsSep 29 2003In 1978, W. Thurston revolutionized low diemsional topology with his work on hyperbolic 3-manifolds. In this paper, we discuss what is currently known about knots in the 3-sphere with hyperbolic complements. Then focus is on geometric invariants coming ... More
350 micron observations of local IRAS galaxies using SHARC-IIDec 12 2003The cosmologically significant population of dusty galaxies detected at sub-mm and mm wavelengths by SCUBA and MAMBO have played a central part in many of the discussions at this workshop. Obtaining their redshifts is critical in understanding their role ... More
Linear structure of Lipschitz-free spaces over countable compact metric spacesMar 04 2016Jun 01 2016In this paper we show that the Lipschitz-free space over some compact metric spaces linearly embed into a l1-sum of finite dimensional subspaces of itself. We also prove that under natural conditions, the Lipschitz-free space over a compact metric space ... More
On Schemmel Nontotient NumbersDec 09 2014For each positive integer $r$, let $S_r$ denote the $r^{th}$ Schemmel totient function, a multiplicative arithmetic function defined by \[S_r(p^{\alpha})=\begin{cases} 0, & \mbox{if } p\leq r; \\ p^{\alpha-1}(p-r), & \mbox{if } p>r \end{cases}\] for all ... More
On Sparsely Schemmel Totient NumbersDec 09 2014For each positive integer $r$, let $S_r$ denote the $r^{th}$ Schemmel totient function, a multiplicative arithmetic function defined by \[S_r(p^{\alpha})=\begin{cases} 0, & \mbox{if } p\leq r; \\ p^{\alpha-1}(p-r), & \mbox{if } p>r \end{cases}\] for all ... More
Approaches to threshold meson productionOct 15 1998Near-threshold data on meson production in nucleon-nucleon scattering are analysed in the short-range limit which permits a quantitative comparison of the production in two and three-body final states. The relative strengths of different meson productions ... More
eta meson production in nucleon-nucleon collisionsAug 03 2010New experimental data are presented on the energy dependence of the total cross sections for the np -> d eta and quasi-two-body pp -> pp eta reactions, where the final diproton is detected at very low excitation energy. Differential cross sections of ... More
SaturnalesJun 24 1998Un choix personnel a ete fait d'evenements memorables du programme de physique realise a Saturne-2 pendant les derniers 20 ans.
Lower Bounds in the Preprocessing and Query Phases of Routing AlgorithmsJan 18 2015Sep 07 2015In the last decade, there has been a substantial amount of research in finding routing algorithms designed specifically to run on real-world graphs. In 2010, Abraham et al. showed upper bounds on the query time in terms of a graph's highway dimension ... More
On the Density of Ranges of Generalized Divisor Functions with Restricted DomainsJul 09 2015We begin by defining functions $\sigma_{t,k}$, which are generalized divisor functions with restricted domains. For each positive integer $k$, we show that, for $r>1$, the range of $\sigma_{-r,k}$ is a subset of the interval $\displaystyle{\left[1,\frac{\zeta(r)}{\zeta((k+1)r)}\right)}$. ... More
A General Approach for Producing Hamiltonian Numerical Schemes for Fluid EquationsJan 26 2005Feb 24 2005Given a fluid equation with reduced Lagrangian $l$ which is a functional of velocity $\MM{u}$ and advected density $D$ given in Eulerian coordinates, we give a general method for semidiscretising the equations to give a canonical Hamiltonian system; this ... More
Nondegenerate $2 \times k \times (k+1)$ HypermatricesJun 14 2016Jun 17 2016We construct an extension of Gaussian elimination to show that if $\mathbb{F}$ is a topological field, then there is a transitive, free, and continuous action of a natural quotient of $GL_k(\mathbb{F}) \times GL_{k+1}(\mathbb{F})$ on the set $M_k(\mathbb{F})$ ... More
Exploring the spectrum of QCD using a space-time latticeSep 21 2005Some past and ongoing explorations of the spectrum of QCD using Monte Carlo simulations on a space-time lattice are described. Glueball masses in the pure-gauge theory are reviewed, and the energies of gluonic excitations in the presence of a static quark-antiquark ... More
Writing Commutators of Commutators as Products of CubesJul 29 2015It is known that commutators of commutators can be written as products of cubes, with the current upper bound on the number of cubes being 60. We discuss how proofs extracted via coset enumeration can be used to investigate this problem, and exhibit a ... More
On the Density of Ranges of Generalized Divisor Functions with Restricted DomainsJul 09 2015Apr 09 2017We begin by defining functions $\sigma_{t,k}$, which are generalized divisor functions with restricted domains. For each positive integer $k$, we show that, for $r>1$, the range of $\sigma_{-r,k}$ is a subset of the interval $\displaystyle{\left[1,\frac{\zeta(r)}{\zeta((k+1)r)}\right)}$. ... More
Ranges of Unitary Divisor FunctionsJul 09 2015Jun 18 2018For any real $t$, the unitary divisor function $\sigma_t^*$ is the multiplicative arithmetic function defined by $\sigma_t^*(p^{\alpha})=1+p^{\alpha t}$ for all primes $p$ and positive integers $\alpha$. Let $\overline{\sigma_t^*(\mathbb N)}$ denote the ... More
On the Density of Ranges of Generalized Divisor FunctionsJun 17 2015The range of the divisor function $\sigma_{-1}$ is dense in the interval $[1,\infty)$. However, the range of the function $\sigma_{-2}$ is not dense in the interval $\displaystyle{\left[1,\frac{\pi^2}{6}\right)}$. We begin by generalizing the divisor ... More
Venus: Key to understanding the evolution of terrestrial planetsMar 31 2017Why are the terrestrial planets so different? Venus should be the most Earth-like of all our planetary neighbours. Its size, bulk composition and distance from the Sun are very similar to those of the Earth. Its original atmosphere was probably similar ... More
On the contribution of fluorescence to Ly$α$ halos (LAHs) around star forming galaxiesMar 15 2016Apr 12 2016We quantify the contribution of Ly$\alpha$ fluorescence to observed spatially extended Ly$\alpha$ halos around Ly$\alpha$ emitters (LAE) at redshift ${\rm z=3.1}$. The key physical quantities that describe the fluorescent signal include (${\it i}$) the ... More
Habitability of waterworlds: runaway greenhouses, atmospheric expansion and multiple climate states of pure water atmospheresMar 16 2015There are four different stable climate states for pure water atmospheres, as might exist on so-called "waterworlds". I map these as a function of solar constant for planets ranging in size from Mars size to 10 Earth-mass. The states are: globally ice ... More
Anti-Power Prefixes of the Thue-Morse WordJul 20 2016Aug 06 2016Recently, Fici, Restivo, Silva, and Zamboni defined a $k$-anti-power to be a word of the form $w_1w_2\cdots w_k$, where $w_1,w_2,\ldots,w_k$ are distinct words of the same length. They defined $AP(x,k)$ to be the set of all positive integers $m$ such ... More
Finiteness properties of profinite groupsFeb 15 2010Broadly speaking, a finiteness property of groups is any generalisation of the property of having finite order. A large part of infinite group theory is concerned with finiteness properties and the relationships between them. Profinite groups are an important ... More
A problem in the Kourovka notebook concerning the number of conjugacy classes of a finite groupOct 30 2008In this paper, we consider Problem 14.44 in the Kourovka notebook, which is a conjecture about the number of conjugacy classes of a finite group. While elementary, this conjecture is still open and appears to elude any straightforward proof, even in the ... More
Production of $η$ Mesons Near ThresholdMar 11 1993It is argued that the strong energy dependence of the $p\, d \rightarrow \,^{3\!}H\!e\, \eta$ cross section near threshold is due to a final state interaction between the $\eta$ meson and the $^3$He nucleus. The large scattering length that this implies ... More
Meson Production at COSY-TOF and COSY-ANKEAug 03 2010The roles of the COSY-TOF and COSY-ANKE spectrometers in the measurement of strange meson production are briefly reviewed, mainly in connection with new results on the pp -> K^+ p Lambda, pp -> K^+ p Sigma^0 and pp -> K^+ n Sigma^+ reactions.
Coupled-channel effects in kaon pair productionNov 29 2008Two coupled channel effects connected with kaon pair production in proton-proton collisions are discussed. (1) Although there is ample evidence that the antikaon is strongly attracted to the recoil protons in pp -> K+pK-p, residual effects of the K+K- ... More
The legacy of the experimental hadron physics programme at COSYNov 22 2016The experimental hadronic physics programme at the COoler SYnchrotron of the Forschungszentrum Juelich terminated at the end of 2014. After describing the accelerator and the associated facilities, a review is presented of the major achievements in the ... More
Schur properties over some Lipschitz-free spacesMar 04 2016Nov 30 2016In this paper we show that the Lipschitz-free space over some proper metric spaces (every closed ball is compact) linearly embed into a $\ell_1$-sum of finite dimensional subspaces of itself. We also prove that under natural conditions, the Lipschitz-free ... More
Binary Codes and Period-$2$ Orbits of Sequential Dynamical SystemsSep 13 2015A sequential dynamical system (SDS) consists of an undirected simple graph $Y$ with vertices $v_1,v_2,\ldots,v_n$, a collection of vertex functions $\{f_{v_i}\}_{i=1}^n$, a permutation $\pi\in S_n$, and a collection of states $A$. The vertices update ... More
Baryon spectroscopy on the lattice: recent resultsAug 08 2003Progress in determining the baryon spectrum using computer simulations of quarks and gluons in lattice QCD are summarized and some future plans are outlined.
The Monte Carlo method in quantum field theoryFeb 20 2007This series of six lectures is an introduction to using the Monte Carlo method to carry out nonperturbative studies in quantum field theories. Path integrals in quantum field theory are reviewed, and their evaluation by the Monte Carlo method with Markov-chain ... More
Interpreting set theory in higher order arithmeticJul 26 2012Feb 15 2013A folk theorem says higher order arithmetic has the proof theoretic strength of set theory with limited power set. This paper makes the theorem precise in terms of several axiom system based on ZF.
The finiteness theorem for invariants of a finite group (translation of Emmy Noether's "Der Endlichkeitsatz der Invarianten endlicher Gruppen")Mar 22 2015A translation of Emmy Noether's paper "Der Endlichkeitsatz der Invarianten endlicher Gruppen" (Mathematische Annalen, vol. 77, 1920, pages 89--92). In Noether's words, the paper gives "an entirely elementary finiteness proof---using only the theory of ... More
Invariant distributions and X-ray transform for Anosov flowsAug 20 2014Dec 21 2015For Anosov flows preserving a smooth measure on a closed manifold $\mathcal{M}$, we define a natural self-adjoint operator $\Pi$ which maps into the space of invariant distributions in $\cap_{u<0} H^{u}(\mathcal{M})$ and whose kernel is made of coboundaries ... More
Tutorial models of the climate and habitability of Proxima Centauri b: a thin atmosphere is sufficient to distribute heat given low stellar fluxAug 25 2016Proxima Centauri b, an Earth-size planet in the habitable zone of our nearest stellar neighbour, has just been discovered. A theoretical framework of synchronously rotating planets, in which the risk of a runaway greenhouse on the sunlight side and atmospheric ... More
Number and Luminosity Evolution of Interacting Galaxies as a Natural explanation for the Galaxy CountsMay 23 1995A newly developed isochrone synthesis algorithm for the photometric evolution of galaxies is described. Two initial mass functions, IMFs, in particular, the recent IMF determined by Kroupa, Tout, and Gilmore, three photometric transformations, and a 1-Gyr-burst ... More
SaturnaliaJun 24 1998A personal choice is made of the highlights of the physics programme carried out at the Saturne-2 facility over the last twenty years.
An Examination of Possible Gravitational Perturbations in the Transit Timing Variations of Exoplanet WASP-3bJun 21 2011Maciejewski et al. (2010) claim to have detected a possible sinusoidal variation in the transit timing variations of exoplanet WASP-3b, which is currently the only known planet orbiting the star WASP-3. According to Maciejewski's analysis, this signal ... More
On the Density of Ranges of Generalized Unitary Divisor FunctionsJul 09 2015For any integer $t$, the unitary divisor function $\sigma_t^*$ is the multiplicative arithmetic function defined by $\sigma_t^*(p^{\alpha})=1+p^{\alpha t}$ for all primes $p$ and positive integers $\alpha$. The range of the unitary divisor function $\sigma_{-1}^*$ ... More
Quadruple crossing number of knots and linksNov 12 2012Jan 28 2013A quadruple crossing is a crossing in a projection of a knot or link that has four strands of the knot passing straight through it. A quadruple crossing projection is a projection such that all of the crossings are quadruple crossings. In a previous paper, ... More
Sinkhorn Divergence of Topological Signature Estimates for Time Series ClassificationFeb 14 2019Distinguishing between classes of time series sampled from dynamic systems is a common challenge in systems and control engineering, for example in the context of health monitoring, fault detection, and quality control. The challenge is increased when ... More
Resonances and scattering poles on asymptotically hyperbolic manifoldsMar 31 2004On an asymptotically hyperbolic manifold (X,g), we show that the resolvent resonances coincide, with multiplicities, with the poles of the renormalized scattering operator, except for the special points n/2-k (with k>0 integer) where an additional term ... More
Generalized Krein formula and determinants for even dimensional Poincare-Einstein manifoldsDec 08 2005Aug 02 2007For a class of even dimensional conformally compact manifolds (X,g), we define a generalized Krein spectral function by applying a renormalized trace functional to the spectral measure of the Laplacian. We then show that this is the phase of the Kontsevich-Vishik ... More
Generalized augmented alternating links and hyperbolic volumeJun 09 2015Augmented alternating links are links obtained by adding trivial components that bound twice-punctured disks to non-split reduced non-2-braid prime alternating projections. These links are known to be hyperbolic. Here, we extend to show that generalized ... More
A univalent universe in finite order arithmeticDec 21 2014Jan 10 2015Homotopy Type Theory with a univalent universe $\,\mathcal{U}_0$ is interpreted at the strength of finite order arithmetic. We eliminate Grothendieck universes, avoid the axiom of replacement, and bound all uses of separation.
Transition from Established Stationary Vision of Black Holes to Never-Stationary Gravitational CollapseJul 16 2010Jul 26 2010The established concept of black hole emerged from several results founded on Einstein's General Theory of Relativity. In this article, the relationship between these results is analyzed, and it is pointed out how, in spite of being individually correct, ... More
Report IAU Comm. 42, Close Binary StarsJun 17 2008Brief summaries are given about (1) close binary research from the perspective of the Bibliography of Close Binaries, (2) low-mass binaries and model discrepancies, (3) W UMa-type binaries, (4) cataclysmic variables, (5) Algol binaries, (6) the oEA stars, ... More
Protoplanetary disk lifetimes vs stellar mass and possible implications for giant planet populationsFeb 02 2015Feb 05 2015We study the dependence of protoplanetary disk evolution on stellar mass using a large sample of young stellar objects in nearby young star-forming regions. We update the protoplanetary disk fractions presented in our recent work (paper I of this series) ... More
Lenses as an Atom-Photon Interface: A Semiclassical ModelDec 03 2010Strong interaction between the light field and an atom is often achieved with cavities. Recent experiments have used a different configuration: a propagating light field is strongly focused using a system of lenses, the atom being supposed to sit at the ... More
A classification of spanning surfaces for alternating linksMay 24 2012A classification of spanning surfaces for alternating links is provided up to genus, orientability, and a new invariant that we call aggregate slope. That is, given an alternating link, we determine all possible combinations of genus, orientability, and ... More
Phototactic Clustering of Swimming Micro-organisms in a Turbulent Velocity FieldFeb 05 2008We study the distribution of swimming micro-organisms advected by a model turbulent flow and attracted towards a localised light source through phototaxis. It is shown that particles aggregate along a dynamical attractor with fractal measure whose dimension ... More
Optimal Quantum Circuits for General Two-Qubit GatesAug 01 2003Mar 25 2004In order to demonstrate non-trivial quantum computations experimentally, such as the synthesis of arbitrary entangled states, it will be useful to understand how to decompose a desired quantum computation into the shortest possible sequence of one-qubit ... More