Results for "Pablo Samuel Castro"

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Combining Learned Lyrical Structures and Vocabulary for Improved Lyric GenerationNov 12 2018The use of language models for generating lyrics and poetry has received an increased interest in the last few years. They pose a unique challenge relative to standard natural language problems, as their ultimate purpose is reative, notions of accuracy ... More
A Comparative Analysis of Expected and Distributional Reinforcement LearningJan 30 2019Since their introduction a year ago, distributional approaches to reinforcement learning (distributional RL) have produced strong results relative to the standard approach which models expected values (expected RL). However, aside from convergence guarantees, ... More
Distributional reinforcement learning with linear function approximationFeb 08 2019Despite many algorithmic advances, our theoretical understanding of practical distributional reinforcement learning methods remains limited. One exception is Rowland et al. (2018)'s analysis of the C51 algorithm in terms of the Cram\'er distance, but ... More
Dopamine: A Research Framework for Deep Reinforcement LearningDec 14 2018Deep reinforcement learning (deep RL) research has grown significantly in recent years. A number of software offerings now exist that provide stable, comprehensive implementations for benchmarking. At the same time, recent deep RL research has become ... More
Shaping the Narrative Arc: An Information-Theoretic Approach to Collaborative DialogueJan 31 2019We consider the problem of designing an artificial agent capable of interacting with humans in collaborative dialogue to produce creative, engaging narratives. In this task, the goal is to establish universe details, and to collaborate on an interesting ... More
Role of viscous friction in the reverse rotation of a diskSep 24 2013May 22 2014The mechanical response of a circularly-driven disk in a dissipative medium is considered. We focus on the role played by viscous friction in the spinning motion of the disk, especially on the effect called reverse rotation, where the intrinsic and orbital ... More
An Atari Model Zoo for Analyzing, Visualizing, and Comparing Deep Reinforcement Learning AgentsDec 17 2018Much human and computational effort has aimed to improve how deep reinforcement learning algorithms perform on benchmarks such as the Atari Learning Environment. Comparatively less effort has focused on understanding what has been learned by such methods, ... More
A Geometric Perspective on Optimal Representations for Reinforcement LearningJan 31 2019This paper proposes a new approach to representation learning based on geometric properties of the space of value functions. We study a two-part approximation of the value function: a nonlinear map from states to vectors, or representation, followed by ... More
Automated Reasoning over Deontic Action Logics with Finite VocabulariesJan 06 2014In this paper we investigate further the tableaux system for a deontic action logic we presented in previous work. This tableaux system uses atoms (of a given boolean algebra of action terms) as labels of formulae, this allows us to embrace parallel execution ... More
Lightest pseudoscalar exchange contribution to light-by-light scattering piece of the muon g-2Sep 07 2014Sep 09 2014Lightest pseudoscalar (P= pi^0, eta, eta') exchange contribution to the light-by-light (LbL) scattering piece of the muon anomaly, a_mu=(g_mu-2)/2, has been evaluated using a resonance chiral Lagrangian (R\chi L). Best description of pion transition form-factor ... More
Marginal Confinement in Tokamaks by Inductive Electric FieldNov 17 2004Here diffusion and Ware pinch are analyzed as opposed effects for plasma confinement, when instabilities are not considered. In this work it is studied the equilibrium inductive electric field where both effects annul each other in the sense that the ... More
On a problem by Dol'nikovOct 17 2013Apr 07 2015In 2011 at an Oberwolfach workshop in Discrete Geometry, V. Dol'nikov posed the following problem. Consider three non-empty families of translates of a convex compact set $K$ in the plane. Suppose that every two translates from different families have ... More
Dynamics and zeta functions on conformally compact manifoldsJun 09 2011Jul 01 2011In this note, we study the dynamics and associated zeta functions of conformally compact manifolds with variable negative sectional curvatures. We begin with a discussion of a larger class of manifolds known as convex co-compact manifolds with variable ... More
Verificarlo: checking floating point accuracy through Monte Carlo ArithmeticSep 04 2015Nov 04 2015Numerical accuracy of floating point computation is a well studied topic which has not made its way to the end-user in scientific computing. Yet, it has become a critical issue with the recent requirements for code modernization to harness new highly ... More
On the Combination of TDDFT with Molecular Dynamics: New DevelopmentsFeb 01 2011In principle, we should not need the time-dependent extension of density-functional theory (TDDFT) for excitations, and in particular not for Molecular Dynamics (MD) studies: the theorem by Hohenberg and Kohn teaches us that for any observable that we ... More
Ambiguities on the Hamiltonian formulation of the free falling particle with quadratic dissipationOct 16 2007For a free falling particle moving in a media which has quadratic velocity force effect on the particle, two equivalent constants of motion, with units of energy, two Lagrangians, and two Hamiltonians are deduced. These quantities describe the dynamics ... More
Anisotropic normal-state properties of the MgB2 superconductorMay 11 2004Based on the experimentally found existence of two gaps in MgB2 (one gap associated to the boron sigma-states and the other to the boron pi-states), the different contributions to the transport properties, electrical conductivity and Hall coefficient, ... More
Simulating Behaviours to face up an Emergency EvacuationJan 21 2014Computer based models describing pedestrian behavior in an emergency evacuation play a vital role in the development of active strategies that minimize the evacuation time when a closed area must be evacuated. The reference model has a hybrid structure ... More
Analysis of the Drift Instability Growth Rates in Non-Ideal inhomogeneous Dusty PlasmasOct 19 2004Nov 05 2004In this paper we introduce an algebraic form of the dispersion relation for a non ideal inhomogeneous dusty plasma in order to improve drastically the calculation of the drift instability growth rate. This method makes use of the multipole approximation ... More
Negative Differential Resistance and Steep Switching in Chevron Graphene Nanoribbon Field Effect TransistorsMar 17 2017Ballistic quantum transport calculations based on the non-equilbrium Green's function formalism show that field-effect transistor devices made from chevron-type graphene nanoribbons (CGNRs) could exhibit negative differential resistance with peak-to-valley ... More
Cluster analysis of homicide rates in the Brazilian state of Goias from 2002 to 2014Nov 11 2018Jan 02 2019Homicide mortality is a worldwide concern and has occupied the agenda of researchers and public managers. In Brazil, homicide is the third leading cause of death in the general population and the first in the 15-39 age group. In South America, Brazil ... More
Extracting Syntactic Patterns from DatabasesOct 31 2017Dec 06 2017Many database columns contain string or numerical data that conforms to a pattern, such as phone numbers, dates, addresses, product identifiers, and employee ids. These patterns are useful in a number of data processing applications, including understanding ... More
Smallify: Learning Network Size while TrainingJun 10 2018As neural networks become widely deployed in different applications and on different hardware, it has become increasingly important to optimize inference time and model size along with model accuracy. Most current techniques optimize model size, model ... More
A modified Ehrenfest formalism for efficient large-scale ab initio molecular dynamicsDec 15 2008Apr 15 2009We present in detail the recently derived ab-initio molecular dynamics (AIMD) formalism [Phys. Rev. Lett. 101 096403 (2008)], which due to its numerical properties, is ideal for simulating the dynamics of systems containing thousands of atoms. A major ... More
$L^p$-boundedness properties for the maximal operators for semigroups associated with Bessel and Laguerre operatorsMar 05 2012In this paper we prove that the generalized (in the sense of Caffarelli and Calder\'on) maximal operators associated with heat semigroups for Bessel and Laguerre operators are weak type (1,1). Our results include other known ones and our proofs are simpler ... More
EDGES result versus CMB and low-redshift constraints on ionization historiesApr 11 2018May 18 2018We examine the results from the Experiment to Detect the Global Epoch of Reionization Signature (EDGES), which has recently claimed the detection of a strong absorption in the 21 cm hyperfine transition line of neutral hydrogen, at redshifts demarcating ... More
Methods for computing state similarity in Markov Decision ProcessesJun 27 2012A popular approach to solving large probabilistic systems relies on aggregating states based on a measure of similarity. Many approaches in the literature are heuristic. A number of recent methods rely instead on metrics based on the notion of bisimulation, ... More
Entrenamiento de una red neuronal para el reconocimiento de imagenes de lengua de senas capturadas con sensores de profundidadMar 22 2018Due to the growth of the population with hearing problems, devices have been developed that facilitate the inclusion of deaf people in society, using technology as a communication tool, such as vision systems. Then, a solution to this problem is presented ... More
Sub-20 nm Nanopores Sculptured by a Single Nanosecond Laser PulseJun 21 2018Single-molecule based 3rd generation DNA sequencing technologies have been explored with tremendous effort, among which nanopore sequencing is considered as one of the most promising to achieve the goal of $1,000 genome project towards personalized medicine. ... More
Analytical parametrization and shape classification of anomalous HH production in the EFT approachJul 19 2016In this document we study the effect of anomalous Higgs boson couplings on non-resonant pair production of Higgs bosons ($HH$) at the LHC. We explore the space of the five parameters $\kappa_{\lambda}$, $\kappa_{t}$, $c_2$, $c_g$, and $c_{2g}$ in terms ... More
World Space Observatory-Ultraviolet: ISSIS, the imaging instrumentFeb 05 2013Jun 04 2013The Imaging and Slitless Spectroscopy Instrument (ISSIS) will be flown as part of the Science Instrumentation in the World Space Observatory-Ultraviolet (WSO-UV). ISSIS will be the first UV imager to operate in a high Earth orbit from a 2-m class space ... More
The RobotriX: An eXtremely Photorealistic and Very-Large-Scale Indoor Dataset of Sequences with Robot Trajectories and InteractionsJan 19 2019Enter the RobotriX, an extremely photorealistic indoor dataset designed to enable the application of deep learning techniques to a wide variety of robotic vision problems. The RobotriX consists of hyperrealistic indoor scenes which are explored by robot ... More
Lagrangian surfaces with circullar ellipse of curvature in complex space formsOct 09 2002We classify the Lagrangian orientable surfaces in complex space forms with the property that the ellipse of curvature is always a circle. As a consequence, we obtain new characterizations of the Clifford torus of the complex projective plane and of the ... More
Complexity of comparing monomials and two improvements of the BM-algorithmJul 15 2008Aug 27 2008We give a new algorithm for merging sorted lists of monomials. Together with a projection technique we obtain a new complexity bound for the BM-algorithm.
Escaping the Tragedy of the Commons through Targeted PunishmentJun 04 2015Failures of cooperation cause many of society's gravest problems. It is well known that cooperation among many players faced with a social dilemma can be maintained thanks to the possibility of punishment, but achieving the initial state of widespread ... More
Interplay between Network Topology and Dynamics in Neural SystemsFeb 16 2013This thesis is a compendium of research which brings together ideas from the fields of Complex Networks and Computational Neuroscience to address two questions regarding neural systems: 1) How the activity of neurons, via synaptic changes, can shape the ... More
Polar actions on Hermitian and quaternion-Kähler symmetric spacesDec 18 2006Jan 17 2007We analyze polar actions on Hermitian and quaternion-K\"ahler symmetric spaces of compact type. For complex integrable polar actions on Hermitian symmetric spaces of compact type we prove a reduction theorem and several corollaries concerning the geometry ... More
The number of points from a random lattice that lie inside a ballNov 12 2013We prove a sharp bound for the remainder term of the number of lattice points inside a ball, when averaging over a compact set of (not necessarily unimodular) lattices, in dimensions two and three. We also prove that such a bound cannot hold if one averages ... More
Chern classes of the tangent bundle on the Hilbert scheme of points on the affine planeOct 21 2004Mar 31 2005The cohomology of the Hilbert schemes of points on smooth projective surfaces can be approached both with vertex algebra tools and equivariant tools. Using the first tool, we study the existence and the structure of universal formulas for the Chern classes ... More
A quantum point contact as a (near) perfect spin polariserNov 28 2018In this paper, I present a simple method of obtaining spin-polarised current from a QPC with a large Rashba interaction. The origin of this spin polarisation is the adiabatic evolution of spin "up" of the first QPC sub-band, into spin "down" of the second ... More
A theoretical framework for retinal computations: insights from textbook knowledgeJun 07 2018Neural circuits in the retina divide the incoming visual scene into more than a dozen distinct representations that are sent on to central brain areas, such as the lateral geniculate nucleus and the superior colliculus. The retina can be viewed as a parallel ... More
Propagation in media as a probe for topological propertiesSep 23 2017The central goal of this thesis is to develop methods to experimentally study topological phases. We do so by applying the powerful toolbox of quantum simulation techniques with cold atoms in optical lattices. To this day, a complete classification of ... More
Real-Time Multiple Object Tracking - A Study on the Importance of SpeedSep 11 2017Oct 02 2017In this project, we implement a multiple object tracker, following the tracking-by-detection paradigm, as an extension of an existing method. It works by modelling the movement of objects by solving the filtering problem, and associating detections with ... More
Context-Independent Polyphonic Piano Onset Transcription with an Infinite Training DatasetJul 26 2017Many of the recent approaches to polyphonic piano note onset transcription require training a machine learning model on a large piano database. However, such approaches are limited by dataset availability; additional training data is difficult to produce, ... More
On Certain Tilting Modules for SL2May 19 2017Sep 19 2017We give a complete picture of when the tensor product of an induced module and a Weyl module is a tilting module for the algebraic group $SL_2$ over an algebraically closed field of characteristic $p$. Whilst the result is recursive by nature, we give ... More
Almost prime values of the order of abelian varieties over finite fieldsMar 09 2018Let $E/\mathbb Q$ be an elliptic curve, and denote by $N(p)$ the number of $\mathbb{F}_p$-points of the reduction modulo $p$ of $E$. A conjecture of Koblitz, refined by Zywina, states that the number of primes $p \leq X$ at which $N(p)$ is also prime ... More
Convergence of the Yang-Mills-Higgs flow on gauged holomorphic maps and applicationsOct 07 2016The symplectic vortex equations admit a variational description as global minimum of the Yang--Mills--Higgs functional. We study its negative gradient flow on holomorphic pairs $(A,u)$ where $A$ is a connection on a principal $G$-bundle $P$ over a closed ... More
Infinitesimal thickenings of Morava K-theoriesJul 05 2006Mar 06 2008A. Baker has constructed certain sequences of cohomology theories which interpolate between the Johnson-Wilson and the Morava K-theories. We realize the representing sequences of spectra as sequences of MU-algebras. Starting with the fact that the spectra ... More
I-adic towers in topologyNov 18 2004Nov 30 2005A large variety of cohomology theories is derived from complex cobordism MU^*(-) by localizing with respect to certain elements or by killing regular sequences in MU_*. We study the relationship between certain pairs of such theories which differ by a ... More
Infinite graphs in systematic biology, with an application to the species problemJan 13 2012Dec 13 2012We argue that C. Darwin and more recently W. Hennig worked at times under the simplifying assumption of an eternal biosphere. So motivated, we explicitly consider the consequences which follow mathematically from this assumption, and the infinite graphs ... More
The global gravitational anomaly of the self-dual field theoryOct 20 2011May 10 2013We derive a formula for the global gravitational anomaly of the self-dual field theory on an arbitrary compact oriented Riemannian manifold. Along the way, we uncover interesting links between the theory of determinant line bundles of Dirac operators, ... More
On weighted optimality of experimental designsOct 20 2016When the experimental objective is expressed by a set of estimable functions, and any eigenvalue-based optimality criterion is selected, we prove the equivalence of the recently introduced weighted optimality and the 'standard' optimality criteria for ... More
The Ngai model of relaxation: An alternative for the study of an interacting system of small particlesJun 10 1996It is shown that the Ngai model of relaxation accounts for the main experimental results of the magnetic relaxation in an assembly of interacting fine particles.
Top-quark mass at hadron collidersApr 14 2014Sep 02 2014Top quarks can be produced abundantly at hadron colliders like the Tevatron at Fermilab and the Large Hadron Collider at CERN, and a variety of measurements of top-quark properties have been gathered in the recent years from four experiments: CDF and ... More
Machine learning of neuroimaging to diagnose cognitive impairment and dementia: a systematic review and comparative analysisApr 05 2018Apr 11 2018INTRODUCTION: Advanced machine learning methods might help to identify dementia risk from neuroimaging, but their accuracy to date is unclear. METHODS: We systematically reviewed the literature, 2006 to late 2016, for machine learning studies differentiating ... More
The Ergodic Closing Lemma for Nonsingular EndomorphismsJun 11 2009Jun 15 2009We prove the ergodic Closing Lemma for Nonsingular Endomorphisms.
New Criteria of Generic Hyperbolicity based on Periodic PointsJun 12 2009Jun 12 2012We prove a criteria for uniform hyperbolicity based on the periodic points of the transformation. More precisely, if a mild (non uniform) hyperbolicity condition holds for the periodic points of any diffeomorphism in a residual subset of a $C^1$-open ... More
Lazy Transformation-Based LearningJun 03 1998We introduce a significant improvement for a relatively new machine learning method called Transformation-Based Learning. By applying a Monte Carlo strategy to randomly sample from the space of rules, rather than exhaustively analyzing all possible rules, ... More
Noncommutativity inspired Black Holes as Dark Matter CandidateApr 17 2015May 30 2016We study a black hole with a blurred mass density instead of a singular one, which could be caused by the noncommutativity of 3-space. Depending on its mass, such object has either none, one or two event horizons. It possesses new properties, which become ... More
f-Vectors of Triangulated BallsDec 10 2009We describe two methods for showing that a vector can not be the f-vector of a homology d-ball. As a consequence, we disprove a conjectured characterization of the f-vectors of balls of dimension five and higher due to Billera and Lee. We also provide ... More
Unimodality of Partitions in Near-Rectangular Ferrers DiagramsAug 18 2014May 20 2015We look at the rank generating function $G_\lambda$ of partitions inside the Ferrers diagram of some partition $\lambda$, investigated by Stanton in 1990, as well as a closely related problem investigated by Stanley and Zanello in 2013. We show that $G_\lambda$ ... More
Ramsey expansions of $Λ$-ultrametric spacesOct 03 2017For a finite lattice $\Lambda$, $\Lambda$-ultrametric spaces are a convenient language for describing structures equipped with a family of equivalence relations. When $\Lambda$ is finite and distributive, there exists a generic $\Lambda$-ultrametric space, ... More
Infinite Limits of Finite-Dimensional Permutation Structures, and their Automorphism Groups: Between Model Theory and CombinatoricsMay 11 2018In the course of classifying the homogeneous permutations, Cameron introduced the viewpoint of permutations as structures in a language of two linear orders, and this structural viewpoint is taken up here. The majority of this thesis is concerned with ... More
Automorphismes naturels de l'espace de Douady de points sur une surfaceMay 27 2009We prove some general results concerning the size of the group of automorphisms of the Douady space of points on a surface. We then study some properties of the automorphisms coming from an automorphism of the surface, in particular their action on the ... More
A survey of the GIT picture for the Yang-Mills equation over Riemann surfacesNov 25 2015Dec 11 2015The purpose of this paper is to give a self-contained exposition of the Atiyah-Bott picture for the Yang-Mills equation over Riemann surfaces with an emphasis on the analogy to finite dimensional geometric invariant theory. The main motivation is to provide ... More
The global anomalies of (2,0) superconformal field theories in six dimensionsJun 17 2014Sep 02 2014We compute the global gauge and gravitational anomalies of the A-type (2,0) superconformal quantum field theories in six dimensions, and conjecture a formula valid for the D- and E-type theories. We show that the anomaly contains terms that do not contribute ... More
The anomaly field theories of six-dimensional (2,0) superconformal theoriesJun 06 2017Jun 16 2017We construct 7-dimensional quantum field theories encoding the anomalies of conformal field theories with (2,0) supersymmetry in six dimensions. We explain how the conformal blocks of the (2,0) theories arise in this context. A result of independent interest ... More
A quantum lower bound for the collision problemApr 24 2003We extend Shi's 2002 quantum lower bound for collision in $r$-to-one functions with $n$ inputs. Shi's bound of $\Omega((n/r)^{1/3})$ is tight, but his proof applies only in the case where the range has size at least $3n/2$. We give a modified version ... More
Analytic Combinatorics of Planar Lattice PathsApr 23 2013Lattice paths effectively model phenomena in chemistry, physics and probability theory. Asymptotic enumeration of lattice paths is linked with entropy in the physical systems being modeled. Lattice paths restricted to different regions of the plane are ... More
Counting nonsingular matrices with primitive row vectorsNov 12 2012May 02 2013We give an asymptotic expression for the number of nonsingular integer n-by-n-matrices with primitive row vectors, determinant k, and Euclidean matrix norm less than T, for large T. We also investigate the density of matrices with primitive rows in the ... More
Homology of powers of regular idealsAug 27 2003For a commutative ring R with an ideal I, generated by a finite regular sequence, we construct differential graded algebras which provide R-free resolutions of I^s and of R/I^s for s>0 and which generalise the Koszul resolution. We derive these from a ... More
A Discrete Inverse Scattering Transform for Q3$_δ$Oct 05 2012We derive a fully discrete Inverse Scattering Transform as a method for solving the initial-value problem for the Q3$_\delta$ lattice (difference-difference) equation for real-valued solutions. The initial condition is given on an infinite staircase within ... More
The Maximum Number of Subset Divisors of a Given SizeJul 17 2014May 20 2015If $s$ is a positive integer and $A$ is a set of positive integers, we say that $B$ is an $s$-divisor of $A$ if $\sum_{b\in B} b\mid s\sum_{a\in A} a$. We study the maximal number of $k$-subsets of an $n$-element set that can be $s$-divisors. We provide ... More
Stable solutions of semilinear elliptic equations in unbounded domainsOct 19 2018This paper establishes some properties for stable solutions of a semilin-ear elliptic equation with homogeneous Neumann boundary conditions in unbounded domains. A seminal result of Casten, Holland [16] and Matano [23] states that, in convex bounded domains, ... More
The Donaldson hyperkähler metric on the almost-Fuchsian moduli spaceSep 04 2018Donaldon constructed a hyperk\"ahler moduli space $\mathcal{M}$ associated to a closed oriented surface $\Sigma$ with $\textrm{genus}(\Sigma) \geq 2$. This embeds naturally into the cotangent bundle $T^*\mathcal{T}(\Sigma)$ of Teichm\"uller space or can ... More
Algorithmic No-Cloning TheoremAug 09 2018We introduce the notions of algorithmic mutual information and rarity of quantum states. These definitions enjoy conservation inequalities over unitary transformations and partial traces. We show that a large majority of pure states have minute self algorithmic ... More
$Λ$-ultrametric spaces and lattices of equivalence relationsNov 27 2018For a finite lattice $\Lambda$, $\Lambda$-ultrametric spaces have, among other reasons, appeared as a means of constructing structures with lattices of equivalence relations embedding $\Lambda$. This makes use of an isomorphism of categories between $\Lambda$-ultrametric ... More
Constant Slope Models for Finitely Generated MapsJul 14 2017We study countably monotone and Markov interval maps. We establish sufficient conditions for uniqueness of a conjugate map of constant slope. We explain how global window perturbation can be used to generate a large class of maps satisfying these conditions. ... More
Boolean ideals and their varietiesNov 14 2012May 25 2015We consider ideals in the ring $\mathbb{Z}_2[x_1,\ldots, x_n]$ that contain the polynomials $x_i^2 - x_i$ for $i = 1, \ldots, n$ and give various results related to the one-to-one correspondence between these ideals and the subsets of $\mathbb{Z}_2^n$. ... More
f-vectors of Simplicial Posets that are BallsSep 10 2010Results of R. Stanley and M. Masuda completely characterize the h-vectors of simplicial posets whose order complexes are spheres. In this paper we examine the corresponding question in the case where the order complex is a ball. Using the face rings of ... More
Minimising Hausdorff Dimension under Hölder EquivalenceJan 18 2019We study the infimal value of the Hausdorff dimension of spaces that are H\"older equivalent to a given metric space; we call this bi-H\"older-invariant "H\"older dimension". This definition and some of our methods are analogous to those used in the study ... More
On the McKay correspondences for the Hilbert scheme of points on the affine planeOct 11 2004The quotient of a finite-dimensional vector space by the action of a finite subgroup of automorphisms is usually a singular variety. Under appropriate assumptions, the McKay correspondence relates the geometry of nice resolutions of singularities and ... More
Towards the multiplicative behavior of the K-theoretical McKay correspondenceJan 24 2005May 01 2005When the quotient of a symplectic vector space by the action of a finite subgroup of symplectic automorphisms admits as a crepant projective resolution of singularities the Hilbert scheme of regular orbits of Nakamura, then there is a natural isomorphism ... More
Biologically Unavoidable SequencesDec 02 2012Feb 05 2013A biologically unavoidable sequence is an infinite gender sequence which occurs in every gendered, infinite genealogical network satisfying certain tame conditions. We show that every eventually periodic sequence is biologically unavoidable (this generalizes ... More
Siegel-Veech constants in H(2)Mar 30 2005Mar 16 2009Abelian differentials on Riemann surfaces can be seen as translation surfaces, which are flat surfaces with cone-type singularities. Closed geodesics for the associated flat metrics form cylinders whose number under a given maximal length generically ... More
On the rate of equidistribution of expanding horospheres in finite-volume quotients of $\mathrm{SL}(2,\mathbb{C})$Dec 08 2015Let $\Gamma$ be a lattice in $G=\mathrm{SL}(2,\mathbb{C})$. We give an effective equidistribution result with precise error terms for expanding translates of pieces of horospherical orbits in $\Gamma\backslash G$. Our method of proof relies on the theory ... More
Finite higher spin transformations from exponentiationFeb 18 2014Mar 19 2015We study the exponentiation of elements of the gauge Lie algebras ${\rm hs}(\lambda)$ of three-dimensional higher spin theories. Exponentiable elements generate one-parameter groups of finite higher spin symmetries. We show that elements of ${\rm hs}(\lambda)$ ... More
Hamiltonian anomalies from extended field theoriesOct 27 2014Apr 22 2015We develop a proposal by Freed to see anomalous field theories as relative field theories, namely field theories taking value in a field theory in one dimension higher, the anomaly field theory. We show that when the anomaly field theory is extended down ... More
Homogeneous 3-dimensional permutation structuresOct 14 2017We provide a classification of the homogeneous 3-dimensional permutation structures, i.e. homogeneous structures in a language of 3 linear orders, partially answering a question of Cameron. We also arrive at a natural description of all known homogeneous ... More
Monte Carlo simulation of 192Ir radioactive source in a phantom designed for brachytherapy dosimetry and source position evaluationNov 25 2018In this report simulations of 192Ir source located inside a phantom designed for measuring the absorbed dose and radioactive source position are presented. Monte Carlo simulations were performed and results were compared with a theoretical model that ... More
Optimal designs for treatment comparisons represented by graphsDec 20 2016Consider an experiment consisting of a set of independent trials for comparing a set of treatments. In each trial, one treatment is chosen and the mean response of the trial is equal to the effect of the chosen treatment. We examine the optimal approximate ... More
Upper Bounds for Non-Congruent Sphere PackingsSep 28 2015We prove upper bounds on the average kissing number $k(\mathcal{P})$ and contact number $C(\mathcal{P})$ of an arbitrary finite non-congruent sphere packing $\mathcal{P}$, and prove an upper bound on the packing density $\delta(\mathcal{P})$ of an arbitrary ... More
A Small Model for the Cohomology of Some Principal BundlesSep 25 2013Let G be a compact, connected and simply connected Lie group, and {\Omega}G the space of the loops in G based at the identity. This note shows a way to compute the cohomology of the total space of a principal {\Omega}G-bundle over a manifold M, from the ... More
Some criteria for the symmetry of stratified water wavesMar 05 2009This paper considers two-dimensional stably stratified steady periodic gravity water waves with surface profiles monotonic between crests and troughs. We provide sufficient conditions under which such waves are necessarily symmetric. This is done by first ... More
Gravity and decoherence: the double slit experiment revisitedJun 14 2017Jan 29 2018The double slit experiment is iconic and widely used in classrooms to demonstrate the fundamental mystery of quantum physics. The puzzling feature is that the probability of an electron arriving at the detector when both slits are open is not the sum ... More
The defect recollement, the MacPherson-Vilonen construction, and pp formulasAug 19 2018Dec 23 2018For any abelian category $\mathcal{A}$, Auslander constructed a localisation $w:\mathrm{fp}(\mathcal{A}^{\mathrm{op}},\mathrm{Ab})\to \mathcal{A}$ called the defect, which is the left adjoint to the Yoneda embedding $Y:\mathcal{A}\to\mathrm{fp}(\mathcal{A}^{\mathrm{op}},\mathrm{Ab})$. ... More
A Contractive Approach to Separable Lyapunov Functions for Monotone SystemsApr 13 2017Oct 24 2017Monotone systems preserve a partial ordering of states along system trajectories and are often amenable to separable Lyapunov functions that are either the sum or the maximum of a collection of functions of a scalar argument. In this paper, we consider ... More
A type of simulation which some experimental evidence suggests we don't live inJul 03 2018Do we live in a computer simulation? I will present an argument that the results of a certain experiment constitute empirical evidence that we do not live in, at least, one type of simulation. The type of simulation ruled out is very specific. Perhaps ... More
Convergence of the Yang-Mills-Higgs flow on gauged holomorphic maps and applicationsOct 07 2016Jan 10 2018The symplectic vortex equations admit a variational description as global minimum of the Yang-Mills-Higgs functional. We study its negative gradient flow on holomorphic pairs $(A,u)$ where $A$ is a connection on a principal $G$-bundle $P$ over a closed ... More
Graphes, moyennabilité et bas du spectre de variétés topologiquement infiniesJan 14 2010From a graph $G$ with constant valency $v$ and a (non-compact) manifold $C$ with $v$ boundary components, we build a $G$-periodic manifold $M$. This process gives a class of topologically infinite manifolds which generalizes periodic manifolds and includes ... More