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Dark trions and biexcitons in WS2 and WSe2 made bright by e-e scatteringJan 05 2017The direct band gap character and large spin-orbit splitting of the valence band edges (at the K and K' valleys) in monolayer transition metal dichalcogenides have put these two-dimensional materials under the spot-light of intense experimental and theoretical ... More

Fast relaxation of photo-excited carriers in 2D transition metal dichalcogenidesOct 21 2015We predict a fast relaxation of photo-excited carriers in monolayer transition metal dichalcogenides (TMDCs), which is mediated by the emission of longitudinal optical (LO) phonons. By evaluating Born effective charges for ${\rm MoS_2, MoSe_2,WS_2}$, ... More

Co-planar streams, pancakes, and angular-momentum exchange in high-z disc galaxiesOct 27 2011Jan 12 2012We study the feeding of massive galaxies at high redshift through streams from the cosmic web using the Mare Nostrum hydro-cosmological simulation. Our statistical sample consists of 350 dark-matter haloes of ~10^12 Msun at z = 2.5. We find that ~70% ... More

Four phases of angular-momentum buildup in high-z galaxies: from cosmic-web streams through an extended ring to disc and bulgeJul 26 2014Jan 04 2015We study the angular-momentum (AM) buildup in high-$z$ massive galaxies using high-resolution cosmological simulations. The AM originates in co-planar streams of cold gas and merging galaxies tracing cosmic-web filaments, and it undergoes four phases ... More

Auger recombination of dark excitons in ${\rm WS_2}$ and ${\rm WSe_2}$ monolayersJul 04 2016We propose a novel phonon assisted Auger process unique to the electronic band structure of monolayer transition metal dichalcogenides (TMDCs), which dominates the radiative recombination of ground state excitons in Tungsten based TMDCs. Using experimental ... More

Hybrid k$\cdot$p tight-binding model for subbands and infrared intersubband optics in few-layer films of transition-metal dichalcogenides: MoS$_2$, MoSe$_2$, WS$_2$ and WSe${}_2$Aug 04 2018We present a density functional theory parametrized hybrid k$\cdot$p tight binding model for electronic properties of atomically thin films of transition-metal dichalcogenides, 2H-$MX_2$ ($M$=Mo, W; $X$=S, Se). We use this model to analyze intersubband ... More

Localized interlayer complexes in heterobilayer transition metal dichalcogenidesFeb 16 2018Jun 01 2018We present theoretical results for the radiative rates and doping-dependent photoluminescence spectrum of interlayer excitonic complexes localized by donor impurities in MoSe$_2$/WSe$_2$ twisted heterobilayers, supported by quantum Monte Carlo calculations ... More

Dissociation of two-dimensional excitons in monolayer WSe2Apr 19 2018Two-dimensional (2D) semiconducting materials are promising building blocks for optoelectronic applications, many of which require efficient dissociation of excitons into free electrons and holes. However, the strongly bound excitons arising from the ... More

Tuning of impurity-bound interlayer complexes in a van der Waals heterobilayerApr 25 2019Due to their unique two-dimensional nature, charge carriers in semiconducting transition metal dichalcogenides (TMDs) exhibit strong unscreened Coulomb interactions and sensitivity to defects and impurities. The versatility of van der Waals layer stacking ... More

Nano-imaging of intersubband transitions in van der Waals quantum wellsJun 25 2018The science and applications of electronics and optoelectronics have been driven for decades by progress in growth of semiconducting heterostructures. Many applications in the infrared and terahertz frequency range exploit transitions between quantized ... More

Resonantly hybridised excitons in moiré superlattices in van der Waals heterostructuresApr 12 2019Atomically-thin layers of two-dimensional materials can be assembled in vertical stacks held together by relatively weak van der Waals forces, allowing for coupling between monolayer crystals with incommensurate lattices and arbitrary mutual rotation. ... More

Extreme scattering events and Galactic dark matterFeb 10 1998Mar 20 1998Extreme Scattering Events (ESEs) are attributed to radio-wave refraction by a cloud of free-electrons crossing the line-of-sight. We present a new model in which these electrons form the photo-ionized 'skin' of an underlying cool, self-gravitating cloud ... More

Thermal stability of cold clouds in galaxy halosJul 02 1999Oct 14 1999We consider the thermal properties of cold, dense clouds of molecular hydrogen and atomic helium. For cloud masses below 10^-1.7 Msun, the internal pressure is sufficient to permit the existence of particles of solid or liquid hydrogen at temperatures ... More

Cosmic snow clouds: self-gravitating gas spheres manifesting hydrogen condensationJun 13 2019We present hydrostatic equilibrium models of spherical, self-gravitating clouds of helium and molecular hydrogen, focusing on the cold, high-density regime where solid- or liquid-hydrogen can form. The resulting structures have masses from 0.1 Msun down ... More

High velocity gas from the Galactic dark haloNov 13 1998We present the germ of a new model for High Velocity Clouds, derived from the idea that the dark matter halo of our Galaxy is in the form of cold, planetary-mass gas clouds. In this picture HVCs arise as a result of disruptive collisions between dark ... More

Order-Revealing Encryption and the Hardness of Private LearningMay 03 2015An order-revealing encryption scheme gives a public procedure by which two ciphertexts can be compared to reveal the ordering of their underlying plaintexts. We show how to use order-revealing encryption to separate computationally efficient PAC learning ... More

Universal localisations and tilting modules for finite dimensional algebrasJul 24 2013We study universal localisations, in the sense of Cohn and Schofield, for finite dimensional algebras and classify them by certain subcategories of our initial module category. A complete classification is presented in the hereditary case as well as for ... More

Fluctuations in Statistical ModelsSep 10 2007The multiplicity fluctuations of hadrons are studied within the statistical hadron-resonance gas model in the large volume limit. The role of quantum statistics and resonance decay effects are discussed. The microscopic correlator method is used to enforce ... More

The Geometry of SU(3)Aug 13 1997The group SU(3) is parameterized in terms of generalized ``Euler angles''. The differential operators of SU(3) corresponding to the Lie Algebra elements are obtained, the invariant forms are found, the group invariant volume element is found, and some ... More

Can STAR $p+p$ data help constrain fragmentation functions for strange hadronsJun 09 2006STAR has measured a variety of strange particle species in $p+p$ collisions at $\sqrt{s}$=200 GeV. These high statistics data are ideal for comparing to existing leading- and next-to-leading order perturbative QCD (pQCD) models. Leading-order (LO) models ... More

On the Convergence of Soft Potential Dynamics to Hard Sphere DynamicsJan 16 2016We address a question raised in the work of Gallagher, Saint-Raymond and Texier (From Newton to Boltzmann: Hard Spheres and Short-range Potentials, Z\"urich Lectures in Advanced Mathematics, EMS, 2013) that concerns the convergence of soft-potential dynamics ... More

Theoretical Aspects of Cosmic AccelerationApr 29 2016Efforts to understand and map the possible explanations for the late time acceleration of the universe have led to a broad range of suggestions, ranging from the cosmological constant and straightforward dark energy, to exotically coupled models, to infrared ... More

A traditional tree-style tableau for LTLApr 13 2016Propositional linear time temporal logic (LTL) is the standard temporal logic for computing applications and many reasoning techniques and tools have been developed for it. Tableaux for deciding satisfiability have existed since the 1980s. However, the ... More

Connected-Sum Decompositions of Surfaces with Minimally-Intersecting Filling PairsMar 10 2016Let $ S_g $ be a closed surface of genus $ g $ and let $ (\alpha, \beta) $ be a filling pair on $ S_g $; then $ i(\alpha, \beta) \geq 2g-1 $, where $ i $ is the (geometric) intersection number. Aougab and Huang demonstrated that (exponentially many) minimally-intersecting ... More

On the Construction of Tight Gabor Frames for $\mathbb{C}^N$Nov 02 2016The construction of finite tight Gabor frames plays an important role in many applications. These applications include significant ones in signal and image processing. We limit ourselves to frames for the finite dimensional Hilbert space $\mathbb{C}^N$. ... More

Distribution of the transfer matrix in disordered wiresFeb 01 2016A closed expression is derived for the probability distribution of the transfer matrix of a particle moving in a one-dimensional system with delta-correlated, weak disorder. The change in the distribution as a function of wire length is described by a ... More

Controlled Algebra for Simplicial Rings and Algebraic K-theoryJan 30 2014Jun 21 2014We develop a version of controlled algebra for simplicial rings. This generalizes the methods which lead to successful proofs of the algebraic K- theory isomorphism conjecture (Farrell-Jones Conjecture) for a large class of groups. This is the first step ... More

Representation of Uncertainty for Limit ProcessesDec 07 2001Many mathematical models utilize limit processes. Continuous functions and the calculus, differential equations and topology, all are based on limits and continuity. However, when we perform measurements and computations, we can achieve only approximate ... More

Dynamical evolution of stellar clustersJun 23 2011The evolution of star clusters is determined by several internal and external processes. Here we focus on two dominant internal effects, namely energy exchange between stars through close encounters (two-body relaxation) and mass-loss of the member stars ... More

Mass loss of stars in star clusters: an energy source for dynamical evolutionSep 10 2012Dense star clusters expand until their sizes are limited by the tidal field of their host galaxy. During this expansion phase the member stars evolve and lose mass. We show that for clusters with short initial relaxation time scales (<~100 Myr) the dynamical ... More

On ad hoc routing with guaranteed deliveryApr 05 2008We point out a simple poly-time log-space routing algorithm in ad hoc networks with guaranteed delivery using universal exploration sequences.

On the Complexity of Real FunctionsFeb 15 2005We develop a notion of computability and complexity of functions over the reals, which seems to be very natural when one tries to determine just how "difficult" a certain function is. This notion can be viewed as an extension of both BSS computability ... More

Continuum Emission by Cooling CloudsNov 17 2007Sep 11 2008The collapse of baryons into the center of a host dark matter halo is accompanied by radiation that may be detectable as compact (< 10 kpc) UV-continuum and Lyman Alpha (hereafter Lya) emission with Lya luminosities as high as ~1e42-1e43 erg/s in halos ... More

Differential and graphical approaches to multistability theory for chemical reaction networksSep 02 2007The use of mathematical models has helped to shed light on countless phenomena in chemistry and biology. Often, though, one finds that systems of interest in these fields are dauntingly complex. In this paper, we attempt to synthesize and expand upon ... More

Path Integral Quantisation of Finite Noncommutative GeometriesJul 05 2000Nov 12 2002We present a path integral formalism for quantising gravity in the form of the spectral action. Our basic principle is to sum over all Dirac operators. The approach is demonstrated on two simple finite noncommutative geometries: the two-point space, and ... More

The effect of linear terms in a quadratic HamiltonianJun 19 2009For a non-relativistic particle subject to a Hamiltonian that is quadratic in position and momentum, with coefficients that may vary with time, it is shown that the effect of the linear terms in the Hamiltonian is just a spatial translation of the wave ... More

Cosmological Perturbations from Cosmic StringsDec 20 1994Some aspects of the theory of cosmological perturbations from cosmic strings and other topological defects are outlined, with particular reference to a simple example: a spatially flat CDM-dominated universe. The conserved energy-momentum pseudo-tensor ... More

Radio Galaxy Clustering at z~0.3Apr 30 2000Radio galaxies are uniquely useful as probes of large-scale structure as their uniform identification with giant elliptical galaxies out to high redshift means that the evolution of their bias factor can be predicted. As the initial stage in a project ... More

EMC effect, short-range nuclear correlations, neutron starsSep 16 2011Oct 25 2011The recent x>1 (e,e') and correlation experiments at momentum transfer Q^2 \ge 2 GeV^2 confirm presence of short-range correlations (SRC) in nuclei mostly build of nucleons. Recently we evaluated in a model independent way the dominant photon contribution ... More

Color transparency: 33 years and still runningNov 10 2007Jan 08 2008I review history of the color transparency (CT) which started with discovery of the $J/\psi$ meson, discovery of high energy CT phenomena and the recent progress in the investigations of CT at intermediate energies.

Spacetimes with SemanticsNov 20 2014Relationships between objects constitute our notion of space. When these relationships change we interpret this as the passage of time. Observer interpretations are essential to the way we understand these relationships. Hence observer semantics are an ... More

A Finite Element framework for computation of protein normal modes and mechanical responseApr 04 2007A coarse-grained computational procedure based on the Finite Element Method is proposed to calculate the normal modes and mechanical response of proteins and their supramolecular assemblies. Motivated by the elastic network model, proteins are modeled ... More

Isometric embeddings of dual polar graphs in Grassmann graphs over finite fieldsOct 04 2015We consider the Grassmann graphs and dual polar graphs over the same finite field and show that, up to graph automorphism, for every dual polar graph there is the unique isometric embedding in the corresponding Grassmann graph.

Characterizations of strong semilinear embeddings in terms of general linear and projective linear groupsJul 16 2012Nov 08 2012Let $V$ and $V'$ be vector spaces over division rings. Suppose $\dim V$ is finite and not less than 3. Consider a mapping $l:V\to V$ with the following property: for every $u\in {\rm GL}(V)$ there is $u'\in {\rm GL}(V')$ such that $lu=u'l$. Our first ... More

Automorphisms of infinite Johnson graphNov 10 2010Dec 24 2010We consider the {\it infinite Johnson graph} $J_{\infty}$ whose vertex set consists of all subsets $X\subset {\mathbb N}$ satisfying $|X|=|{\mathbb N}\setminus X|=\infty$ and whose edges are pairs of such subsets $X,Y$ satisfying $|X\setminus Y|=|Y\setminus ... More

Magnetically-Driven Winds from Protostellar DisksJul 21 1997Jul 22 1997Angular momentum transport in protostellar disks can be achieved by the action of a large scale magnetic field that runs vertically through the disk. The magnetic field centrifugally drives material from the disk surfaces into a wind, initiating a bipolar ... More

Dust grains and the structure of steady C-type magnetohydrodynamic shock waves in molecular cloudsFeb 20 1998May 08 1998I examine the role of dust grains in determining the structure of steady, cold, oblique C-type shocks in dense molecular gas. Gas pressure, the inertia of the charged components, and changes in ionisation are neglected. The grain charge and rate coefficients ... More

Clusters of Galaxies at z > 1Dec 18 1996Although field galaxy studies have begun to probe the universe at z > 1, evidence for galaxy clusters at such redshifts has been sparse. New observations are accumulating rapidly, however, providing new data on the early evolution of elliptical galaxies, ... More

Color-Selected High Redshift Galaxies and the HDFFeb 05 1998Apr 20 1998The quality, depth, and multi-color nature of the Hubble Deep Field images makes them an excellent resource for studying galaxies at z > 2 using selection techniques based on the presence of the 912A Lyman break. I present a descriptive review of this ... More

Cluster Ellipticals at High Redshift: The View from the Ground and with HSTJul 16 1995New ground-based and HST observations of distant clusters make it possible to trace the history of E/S0 galaxies to lookback times of ~10 $h_{50}^{-1}$ Gyr. The data strongly favor a scenario in which cluster ellipticals formed very early with a narrow ... More

Nonclassical Degrees of Freedom in the Riemann HamiltonianMay 12 2011Nov 14 2011The Hilbert-Polya conjecture states that the imaginary parts of the zeros of the Riemann zeta function are eigenvalues of a quantum hamiltonian. If so, conjectures by Katz and Sarnak put this hamiltonian in Altland and Zirnbauer's universality class C. ... More

The Onset of Chaos in the Quantum Hard-Sphere GasMay 20 1996We show that the condition for the appearance of quantum chaos (Wigner-Dyson distribution of energy eigenvalues, gaussian-random energy eigenfunctions) in a dilute gas of many hard spheres is $\lambda \ll \ell$, where $\lambda$ is the wavelength of a ... More

The Berry-Keating Hamiltonian and the Local Riemann HypothesisApr 11 2011May 31 2011The local Riemann hypothesis states that the zeros of the Mellin transform of a harmonic-oscillator eigenfunction (on a real or p-adic configuration space) have real part 1/2. For the real case, we show that the imaginary parts of these zeros are the ... More

The approach to thermal equilibrium in quantized chaotic systemsSep 25 1998Nov 16 1998We consider many-body quantum systems that exhibit quantum chaos, in the sense that the observables of interest act on energy eigenstates like banded random matrices. We study the time-dependent expectation values of these observables, assuming that the ... More

IIB or not IIBJul 19 1998Sep 03 1998We consider Type IIB superstring theory with the addition of n 9-branes and n anti-9-branes (and no orientifolds). The result is a ten-dimensional chiral theory of open and closed oriented strings with gauge group U(n) \times U(n). There is, however, ... More

Thermal Fluctuations in Quantized Chaotic SystemsNov 10 1995Dec 15 1995We consider a quantum system with $N$ degrees of freedom which is classically chaotic. When $N$ is large, and both $\hbar$ and the quantum energy uncertainty $\Delta E$ are small, quantum chaos theory can be used to demonstrate the following results: ... More

Hydrodynamic Detonation Instability in Electroweak and QCD Phase TransitionsMay 18 1993The hydrodynamic stability of deflagration and detonation bubbles for a first order electroweak and QCD phase transition has been discussed recently with the suggestion that detonations are stable. We examine here the case of a detonation more carefully. ... More

Boundary Forelli theorem for the sphere in $\mathbb C^n$ and $n+1$ bundles of complex linesMar 31 2010Let $B^n$ be the unit ball in $\mathbb C^n$ and let the points $a_1,...,a_{n+1} \in B^n $ are affinely independent. If $f \in C(\partial B^n)$ and for any complex line $L$, containing at least one of the points $a_j$, the restriction $f|_{L \cap \partial ... More

Open charm spectroscopy at LHCbSep 01 2015Recent charm spectroscopy results from Dalitz plot analyses of $B$ decays to open charm final states at LHCb are presented. The decay modes used are $B^{+} \to D^{-} K^{+} \pi^{+}$, $B^{0} \to \overline{D}{}^{0} \pi^{+} \pi^{-}$ and $B^{0} \to \overline{D}{}^{0} ... More

Large Rapidity Gap Events in DISJun 18 1997Diffractive scattering in DIS is discussed in terms of the perturbative two-gluon model and numerical results for $F_2^D$ are presented.

An Introduction to the Quantum Theory of Nonlinear OpticsJan 22 2009This article is provides an introduction to the quantum theory of optics in nonlinear dielectric media. We begin with a short summary of the classical theory of nonlinear optics, that is nonlinear optics done with classical fields. We then discuss the ... More

Quantum cryptography with squeezed statesSep 01 1999A quantum key distribution scheme based on the use of displaced squeezed vacuum states is presented. The states are squeezed in one of two field quadrature components, and the value of the squeezed component is used to encode a character from an alphabet. ... More

The monodromies of homogeneous linksJun 30 2012We show that there are only finitely many homogeneous links whose Conway polynomial has any given degree. Using this we give an example of an inhomogeneous, fibred knot. Secondly, we show how to compute the monodromy of a homogeneous link complement from ... More

A Nondivergence Parabolic Problem with a Fractional Time derivativeJul 15 2015We study a nonlocal nonlinear parabolic problem with a fractional time derivative. We prove a Krylov-Safonov type result; mainly, we prove Holder regularity of solutions. Our estimates remain uniform as the order of the fractional time derivative approaches ... More

Caputo Standard $α$-Family of Maps: Fractional Difference vs. FractionalJun 16 2014In this paper the author compares behaviors of systems which can be described by fractional differential and fractional difference equations using the fractional and fractional difference Caputo Standard $\alpha$-Families of Maps as examples. The author ... More

How much is enough?: Data requirements for statistical NLPSep 07 1995In this paper I explore a number of issues in the analysis of data requirements for statistical NLP systems. A preliminary framework for viewing such systems is proposed and a sample of existing works are compared within this framework. The first steps ... More

Corpus Statistics Meet the Noun Compound: Some Empirical ResultsApr 28 1995Sep 10 1996A variety of statistical methods for noun compound analysis are implemented and compared. The results support two main conclusions. First, the use of conceptual association not only enables a broad coverage, but also improves the accuracy. Second, an ... More

Formalizing Category Theory and Presheaf Models of Type Theory in NuprlJun 15 2018This article is the first in a series of articles that explain the formalization of a constructive model of cubical type theory in Nuprl. In this document we discuss only the parts of the formalization that do not depend on the choice of base category. ... More

A Weyl-Dirac Cosmological Model with DM and DEAug 04 2010In the Weyl-Dirac (W-D) framework a spatially closed cosmological model is considered. It is assumed that the space-time of the universe has a chaotic Weylian microstructure but is described on a large scale by Riemannian geometry. Locally fields of the ... More

Cluster Computing White PaperApr 25 2000Jan 11 2001Cluster computing is not a new area of computing. It is, however, evident that there is a growing interest in its usage in all areas where applications have traditionally used parallel or distributed computing platforms. The growing interest has been ... More

Cobordism Invariance of the Homotopy Type of the Space of Positive Scalar Curvature MetricsSep 30 2011We show that the homotopy type of the space of metrics of positive scalar curvature on a smooth manifold remains unchanged, after application of surgery in codimension at least three to the underlying manifold. This result is originally due to V. Chernysh, ... More

A Tour of T-duality: Geometric and Topological Aspects of T-dualitiesApr 07 2019The primary focus of this thesis is to investigate the mathematical and physical properties of spaces that are related by T-duality and its generalisations. In string theory, T-duality is a relationship between two a priori different string backgrounds ... More

The effect of alternative tree representations on tree bank grammarsNov 20 1997Nov 21 1997The performance of PCFGs estimated from tree banks is sensitive to the particular way in which linguistic constructions are represented as trees in the tree bank. This paper presents a theoretical analysis of the effect of different tree representations ... More

Differentiation in Bundles with a Hyperspace BaseDec 15 2011It is possible to perform some operations with extrafunctions applying these operations separately to each coordinate. Operations performed in this manner are called regular. It is proved that it is possible to extend several operations with functions ... More

Row products of random matricesFeb 09 2011Jun 06 2012We define the row product of K matrices of size d by n as a matrix of size d^K by n, whose row are entry-wise products of rows of these matrices. This construction arises in certain computer science problems. We study the question, to which extent the ... More

Invertibility of random matrices: norm of the inverseJul 01 2005Let A be an n by n matrix, whose entries are independent copies of a centered random variable satisfying the subgaussian tail estimate. We prove that the operator norm of A^{-1} does not exceed Cn^{3/2} with probability close to 1.

On Fractional Eulerian Numbers and Equivalence of Maps with Long Term Power-Law Memory (Integral Volterra Equations of the Second Kind) to Gr$\ddot{u}$nvald-Letnikov Fractional Difference (Differential) EquationsOct 25 2014Dec 23 2014In this paper we consider a simple general form of a deterministic system with power-law memory whose state can be described by one variable and evolution by a generating function. A new value of the system's variable is a total (a convolution) of the ... More

Fractional Maps and Fractional Attractors. Part II: Fractional Difference $α$-Families of MapsApr 19 2014Jun 08 2014In this paper we extend the notion of an $\alpha$-family of maps to discrete systems defined by simple difference equations with the fractional Caputo difference operator. The equations considered are equivalent to maps with falling factorial-law memory ... More

Anisimov's Theorem for inverse semigroupsMar 21 2013The idempotent problem of a finitely generated inverse semigroup is the formal language of all words over the generators representing idempotent elements. This note proves that a finitely generated inverse semigroup with regular idempotent problem is ... More

Some remarks on Heegner point computationsJun 16 2005Apr 05 2006We explain how to find a rational point on a rational elliptic curve of rank 1 using Heegner points. We give some examples, and list new algorithms that are due to Cremona and Delaunay. These are notes from a short course given at the Institut Henri Poincare ... More

Counting rectangles and an improved restriction estimate for the paraboloid in $F_p^3$Jan 29 2019Feb 03 2019Given $A \subset F_{p}^2$ a sufficiently small set in the plane over a prime residue field, we prove that there are at most $O_\epsilon (|A|^{\frac{99}{41}+\epsilon})$ rectangles with corners in $A$. The exponent $\frac{99}{41} = 2.413\ldots$ improves ... More

The ranks of alternating string C-groupsJan 07 2019In this paper, string C-groups of all ranks $3 \leq r \leq \frac{n}{2}$ are provided for each alternating group $A_n$, $n \geq 12$. As the string C-group representations of $A_n$ have also been classified for $n \leq 11$, and it is known that larger ranks ... More

Chasing Convex Bodies OptimallyMay 28 2019In the chasing convex bodies problem, an online player receives a request sequence of $N$ convex sets $K_1,\dots, K_N$ contained in a normed space $\mathbb R^d$. The player starts at $x_0\in \mathbb R^d$, and after observing each $K_n$ picks a new point ... More

Single site factors of Gibbs measuresMay 09 2019It has been an open problem to identify classes of Gibbs measures less regular then H\"older continuous on the full shift which are closed under factor maps. In this article we show that in fact all of the classical uniqueness regimes (Bowen, Walters, ... More

Analytical tools for single-molecule fluorescence imaging in celluloApr 14 2015Recent technological advances in cutting-edge ultrasensitive fluorescence microscopy have allowed single-molecule imaging experiments in living cells across all three domains of life to become commonplace. Single-molecule live-cell data is typically obtained ... More

Del Pezzo Surfaces of degree 6 over an arbitrary fieldMay 01 2008May 02 2008We give a characterization of all del Pezzo surfaces of degree 6 over an arbitrary field $F$. A surface is determined by a pair of separable algebras. These algebras are used to compute the Quillen $K$-theory of the surface. As a consequence, we obtain ... More

Topological complexity of motion planning and Massey productsSep 14 2007Jan 15 2008We employ Massey products to find sharper lower bounds for the Schwarz genus of a fibration than those previously known. In particular we give examples of non-formal spaces $X$ for which the topological complexity $\TC(X)$ (defined to be the genus of ... More

The Caratheodory Topology for Multiply Connected Domains IIMar 13 2011Dec 18 2011We continue our exposition concerning the Caratheodory topology for multiply connected domains by introducing the notion of boundedness for a family of pointed domains of the same connectivity. The limit of a convergent sequence of n-connected domains ... More

Congruences between modular forms given by the divided beta family in homotopy theoryApr 02 2008May 02 2008We characterize the 2-line of the p-local Adams-Novikov spectral sequence in terms of modular forms satisfying a certain explicit congruence condition for primes p > 3. We give a similar characterization of the 1-line, reinterpreting some earlier work ... More

Continuity of ring *-homomorphisms between C*-algebrasOct 02 2008May 05 2009The purpose of this short note is to prove that if $A$ and $B$ are unital C*-algebras and $\phi : A \to B$ is a unital *-preserving ring homomorphism, then $\phi$ is contractive; i.e., $\| \phi (a) \| \leq \| a \|$ for all $a \in A$. (Note that we do ... More

On self-intersection invariantsNov 14 2011Aug 09 2012We prove that the Hatcher-Quinn and Wall invariants of a self-transverse immersion $f\co N^n\imm M^{2n}$ coincide. That is, we construct an isomorphism between their target groups which carries one onto the other. We also employ methods of normal bordism ... More

Transformations of Grassmannians and automorphisms of linear groupsJun 25 2001We consider transformations preserving certain linear structure in Grassmannians and give some generalization of the Fundamental Theorem of Projective Geometry and the Chow Theorem [Ch]. It will be exploited to study linear $(k,n-k)$-involutions, $1<k<n-1$. ... More

A Straightening Theorem for non-Autonomous IterationJun 22 2011Jan 26 2012The classical straightening theorem as proved by Douady and Hubbard shows that a polynomial-like sequence is hybrid equivalent to a polynomial. We generalize this result to non-autonomous iteration where one considers composition sequences arising from ... More

Parabolic Julia Sets are Polynomial Time ComputableMay 03 2005Jun 22 2005In this paper we prove that parabolic Julia sets of rational functions are locally computable in polynomial time.

A Nondivergence Parabolic Problem with a Fractional Time derivativeJul 15 2015May 03 2017We study a nonlocal nonlinear parabolic problem with a fractional time derivative. We prove a Krylov-Safonov type result; mainly, we prove Holder regularity of solutions. Our estimates remain uniform as the order of the fractional time derivative approaches ... More

A note on optimal probability lower bounds for centered random variablesMar 05 2008Apr 24 2008In this note we obtain lower bounds for $\P(\xi\geq 0)$ and $\P(\xi>0)$ under assumptions on the moments of a centered random variable $\xi$. The obtained estimates are shown to be optimal and improve results from the literature. The results are applied ... More

Interpretations of Negative ProbabilitiesAug 06 2010In this paper, we give a frequency interpretation of negative probability, as well as of extended probability, demonstrating that to a great extent, these new types of probabilities, behave as conventional probabilities. Extended probability comprises ... More

Numerical Recovery of Source Singularities via the Radiative Transfer Equation with Partial DataJul 21 2012May 22 2013The inverse source problem for the radiative transfer equation is considered, with partial data. Here we demonstrate numerical computation of the normal operator $X_{V}^{*}X_{V}$ where $X_{V}$ is the partial data solution operator to the radiative transfer ... More

Rationality, Cooperation and Conversational ImplicatureJun 05 1998Conversational implicatures are usually described as being licensed by the disobeying or flouting of a Principle of Cooperation. However, the specification of this principle has proved computationally elusive. In this paper we suggest that a more useful ... More

Searching for knights and spies: a majority/minority gameDec 13 2014There are n people, each of whom is either a knight or a spy. It is known that at least k knights are present, where n/2 < k < n. Knights always tell the truth. We consider both spies who always lie and spies who answer as they see fit. This paper determines ... More