Results for "Alex Alcocer"

total 6117took 0.12s
Achieving Connectivity Between Wide Areas Through Self-Organising Robot Swarm Using Embodied EvolutionJul 12 2018Abruptions to the communication infrastructure happens occasionally, where manual dedicated personnel will go out to fix the interruptions, restoring communication abilities. However, sometimes this can be dangerous to the personnel carrying out the task, ... More
Towards autonomous ocean observing systems using Miniature Underwater Gliders with UAV deployment and recovery capabilitiesFeb 08 2019This paper presents preliminary results towards the development of an autonomous ocean observing system using Miniature Underwater Gliders (MUGs) that can operate with the support of Unmanned Aerial Vehicles (UAVs) and Unmanned Surface Vessels (USVs) ... More
Coulomb drag in quantum circuitsSep 09 2008Oct 22 2008We study drag effect in a system of two electrically isolated quantum point contacts (QPC), coupled by Coulomb interactions. Drag current exhibits maxima as a function of QPC gate voltages when the latter are tuned to the transitions between quantized ... More
Coulomb drag at zero temperatureOct 08 2007We show that the Coulomb drag effect exhibits saturation at small temperatures, when calculated to the third order in the interlayer interactions. The zero-temperature transresistance is inversely proportional to the third power of the dimensionless sheet ... More
Keldysh Ginzburg-Landau action of fluctuating superconductorsJun 19 2007Sep 24 2007We derive Ginzburg-Landau action by systematically integrating out electronic degrees of freedom in the framework of the Keldysh nonlinear sigma-model of disordered superconductors. The resulting Ginzburg-Landau functional contains a nonlocal $\Delta$-dependent ... More
Keldysh technique and non-linear sigma-model: basic principles and applicationsJan 23 2009Apr 27 2009The purpose of this review is to provide a comprehensive pedagogical introduction into Keldysh technique for interacting out-of-equilibrium fermionic and bosonic systems. The emphasis is placed on a functional integral representation of underlying microscopic ... More
Ocean gravitational-modes in transient neutron starsNov 30 2015The neutron star ocean is a plasma of ions and electrons that extends from the base of the neutron star's envelope to a depth where the plasma crystallizes into a solid crust. During an accretion outburst in an X-ray transient, material accumulates in ... More
The spectral norm error of the naive Nystrom extensionOct 24 2011The naive Nystrom extension forms a low-rank approximation to a positive-semidefinite matrix by uniformly randomly sampling from its columns. This paper provides the first relative-error bound on the spectral norm error incurred in this process. This ... More
Special relativity as classical kinematics of a particle with the upper bound on its speed. Part II. The general Lorentz transforrmation and the generalized velocity composition theoremMay 09 2014The kinematics of a particle with the upper bound on the particle's speed (a modification of classical kinematics where such a restriction is absent) has been developed in [arXiv:1204.5740]. It was based solely on classical mechanics without employing ... More
A Short Note on Mapping CylindersJun 06 2012Jul 13 2012Given a homotopy equivalence f between two topological spaces we assemble well known pieces and unfold them into an explicit formula for a strong deformation retraction of the mapping cylinder of f onto its top.
Extending and Characterizing Quantum Magic GamesSep 18 2012The Mermin-Peres magic square game is a cooperative two-player nonlocal game in which shared quantum entanglement allows the players to win with certainty, while players limited to classical operations cannot do so, a phenomenon dubbed "quantum pseudo-telepathy". ... More
Resolving disagreement for eta/s in a CFT plasma at finite couplingMay 17 2008The ratio of shear viscosity to entropy density in a strongly coupled CFT plasma can be computed using the AdS/CFT correspondence either from equilibrium correlation functions or from the Janik-Peschanski dual of the boost invariant plasma expansion. ... More
N=2* hydrodynamicsJun 23 2004Using gauge theory /string theory correspondence certain universal aspects of the strongly coupled four dimensional gauge theory hydrodynamics were established in hep-th/0311175. The analysis were performed in the framework of ``membrane paradigm'' approach ... More
Localization and holography in N=2 gauge theoriesApr 20 2013Sep 18 2013We compare exact results from Pestun's localization of SU(N) N=2^* gauge theory on S^4 with available holographic models. While localization can explain the Coulomb branch vacuum of the holographic Pilch-Warner flow, it disagrees with the holographic ... More
Quantum phase transitions in cascading gauge theoryAug 30 2011We study a ground state of N=1 supersymmetric SU(K+P) x SU(K) cascading gauge theory of Klebanov [1,2] on R x S^3 at zero temperature. A radius of S^3 sets a compactification scale mu. An interplay between mu and the strong coupling scale Lambda ... More
On SUGRA description of boost-invariant conformal plasma at strong couplingMar 24 2008Mar 26 2008We study string theory duals of the expanding boost invariant conformal gauge theory plasmas at strong coupling. The dual supergravity background is constructed as an asymptotic late-time expansion, corresponding to equilibration of the gauge theory plasma. ... More
Bulk viscosity of gauge theory plasma at strong couplingAug 27 2007Sep 01 2007We propose a lower bound on bulk viscosity of strongly coupled gauge theory plasmas. Using explicit example of the N=2^* gauge theory plasma we show that the bulk viscosity remains finite at a critical point with a divergent specific heat. We present ... More
Transport properties of cascading gauge theoriesSep 12 2005Cascading gauge theories of Klebanov provide a model within a framework of gauge theory/string theory duality for a four dimensional non-conformal gauge theory with a spontaneously generated mass scale. Using the dual supergravity description we ... More
On effective action of string theory flux compactificationsDec 07 2003Feb 12 2004We discuss four dimensional effective actions of string theory flux compactifications. These effective actions describe four dimensional gravity coupled to overall Kahler modulus of the compactification manifold. We demonstrate the agreement between ten ... More
On the thermodynamic instability of LSTJul 12 2001Jul 20 2001The high energy thermodynamics of Little String Theory (LST) is known to be unstable. An unresolved question is whether the corresponding instability in LST holographic dual is of stringy or supergravity origin. We study UV thermodynamics of a large metric ... More
New type scalar fields for cosmic accelerationJun 07 2006We present a model where a non-conventional scalar field may act like dark energy leading to cosmic acceleration. The latter is driven by an appropriate field configuration, which result in an effective cosmological constant. The potential role of such ... More
A Direct Sampler for G-Wishart VariatesApr 04 2013The G-Wishart distribution is the conjugate prior for precision matrices that encode the conditional independencies of a Gaussian graphical model. While the distribution has received considerable attention, posterior inference has proven computationally ... More
Nested Bethe Ansatz and Finite Dimensional Canonical Commutation RelationsApr 24 2000Recent interest in discrete, classical integrable systems has focused on their connection to quantum integrable systems via the Bethe equations. In this note, solutions to the rational nested Bethe ansatz (RNBA) equations are constructed using the ``completed ... More
Spectral Difference Equations Satisfied by KP Soliton WavefunctionsNov 11 1998The Baker-Akhiezer (wave) functions corresponding to soliton solutions of the KP hierarchy are shown to satisfy eigenvalue equations for a commutative ring of translational operators in the spectral parameter. In the rational limit, these translational ... More
Bispectrality of $N$-Component KP Wave Functions: A Study in Non-CommutativityMay 11 2015Nov 01 2015A wave function of the $N$-component KP Hierarchy with continuous flows determined by an invertible matrix $H$ is constructed from the choice of an $MN$-dimensional space of finitely-supported vector distributions. This wave function is shown to be an ... More
Grassmannians, Nonlinear Wave Equations and Generalized Schur FunctionsNov 11 1998Feb 26 1999A set of functions is introduced which generalizes the famous Schur polynomials and their connection to Grasmannian manifolds. These functions are shown to provide a new method of constructing solutions to the KP hierarchy of nonlinear partial differential ... More
Bispectral KP Solutions and Linearization of Calogero-Moser Particle SystemsDec 14 1994Dec 15 1994A new construction using finite dimensional dual grassmannians is developed to study rational and soliton solutions of the KP hierarchy. In the rational case, properties of the tau function which are equivalent to bispectrality of the associated wave ... More
Schwarz triangle mappings and Teichmüller curves: abelian square-tiled surfacesMar 13 2012Oct 17 2012We consider normal covers of CP^1 with abelian deck group, branched over at most four points. Families of such covers yield arithmetic Teichm\"uller curves, whose period mapping may be described geometrically in terms of Schwarz triangle mappings. These ... More
Ground state of a large number of particles on a frozen topographyJan 25 2006Problems consisting in finding the ground state of particles interacting with a given potential constrained to move on a particular geometry are surprisingly difficult. Explicit solutions have been found for small numbers of particles by the use of numerical ... More
Crossover in the local density of states of mesoscopic SNS junctionsMay 05 2008Andreev levels deplete energy states above the superconductive gap, which leads to the peculiar nonmonotonous crossover in the local density of states of mesoscopic superconductor/normal-metal/superconductor junctions. This effect is especially pronounced ... More
A Note on Optimality of Quantum Circuits over Metaplectic BasisJun 07 2016Jun 09 2016Metaplectic quantum basis is a universal multi-qutrit quantum basis, formed by the ternary Clifford group and the axial reflection gate $R=|0\rangle \langle 0| + |1\rangle \langle 1| - |2\rangle \langle 2|$. It is arguably, a ternary basis with the simplest ... More
Applications of Thin OrbitsJun 20 2016This text is based on a series of three expository lectures on a variety of topics related to "thin orbits," as delivered at Durham University's Easter School on "Dynamics and Analytic Number Theory" in April 2014. The first lecture reviews closed geodesics ... More
Tensor networks for dynamic spacetimesNov 18 2016Existing tensor network models of holography are limited to representing the geometry of constant time slices of static spacetimes. We study the possibility of describing the geometry of a dynamic spacetime using tensor networks. We find it is necessary ... More
Physics and Chemistry of Purcell's AlignmentJan 17 1995Paramagnetic alignment of suprathermally rotating grains is discussed in view of recent progress in understanding subtle processes taking place over grain surface. It is shown that in typical ISM conditions, grains with surfaces of amorphous H$_{2}$O ... More
On the biregular geometry of Fulton-MacPherson configuration spacesMar 22 2016Let $X[n]$ be the Fulton-MacPherson configuration space of $n$ ordered points on a smooth projective variety $X$. We prove that if either $n\neq 2$ or $\dim(X)\geq 2$, then the connected component of the identity of $Aut(X[n])$ is isomorphic to the connected ... More
Maximum screening fields of superconducting multilayer structuresJan 07 2015It is shown that a multilayer comprised of alternating thin superconducting and insulating layers on a thick substrate can fully screen the applied magnetic field exceeding the superheating fields $H_s$ of both the superconducting layers and the substrate, ... More
Quantum tasks in holographyFeb 19 2019Apr 16 2019We consider an operational restatement of the holographic principle, which we call the principle of asymptotic quantum tasks. Asymptotic quantum tasks are quantum information processing tasks with inputs given and outputs required on points at the boundary ... More
Exponential concentration of cover timesJul 29 2014We prove an exponential concentration bound for cover times of general graphs in terms of the Gaussian free field, extending the work of Ding-Lee-Peres and Ding. The estimate is asymptotically sharp as the ratio of hitting time to cover time goes to zero. ... More
Cosmology with extragalactic proper motions: harmonic formalism, estimators, and forecastsNov 13 2018We conduct a thorough study into the feasibility of measuring large-scale correlated proper motions of galaxies with astrometric surveys. We introduce a harmonic formalism for analysing proper motions and their correlation functions on the sphere based ... More
Ocean g-modes on transient neutron starsNov 30 2015Nov 17 2016The neutron star ocean is a plasma of ions and electrons that extends from the base of the neutron star's envelope to a depth where the plasma crystallizes into a solid crust. During an accretion outburst in an X-ray transient, material accumulates in ... More
Binary Quadratic Forms in Difference SetsOct 08 2018We show that if $h(x,y)=ax^2+bxy+cy^2\in \mathbb{Z}[x,y]$ satisfies $b^2\neq 4ac$, then any subset of $\{1,2,\dots,N\}$ with no nonzero differences in the image of $h$ has size at most a constant depending on $h$ times $N\exp(-c\sqrt{\log N})$, where ... More
Disjoint $n$-amalgamation and pseudofinite countably categorical theoriesOct 13 2015Sep 17 2018Disjoint $n$-amalgamation is a condition on a complete first-order theory specifying that certain locally consistent families of types are also globally consistent. In this paper, we show that if a countably categorical theory $T$ admits an expansion ... More
Scalar SupersymmetryAug 09 2012Dec 02 2013We describe a new realization of supersymmetry, called scalar supersymmetry, acting in spaces of differential forms (bi-spinors), where transformation parameters are Lorentz scalars instead of spinors. The realization is related but is not reducible to ... More
Scalar Supersymmetry in Bi-Spinor Gauge TheoryFeb 25 2013May 20 2013We describe a new realization of both global and local supersymmetry acting in spaces of commuting and anticommuting differential forms. Unlike the standard supersymmetry, it has Lorentz scalar transformation parameters. It is related but is not reducible ... More
Game-Theoretic Optimal Portfolios in Continuous TimeJun 05 2019We consider a two-person trading game in continuous time whereby each player chooses a constant rebalancing rule $b$ that he must adhere to over $[0,t]$. If $V_t(b)$ denotes the final wealth of the rebalancing rule $b$, then Player 1 (the `numerator player') ... More
The Laws of Motion of the Broker Call Rate in the United StatesJun 03 2019In this paper, which is the third installment of the author's trilogy on margin loan pricing, we analyze $1,367$ monthly observations of the U.S. broker call money rate, which is the interest rate at which stock brokers can borrow to fund their margin ... More
Mirzakhani's work on earthquake flowOct 17 2018We give an expository account of Mirzakhani's theorem that earthquake flow and Teichmuller unipotent flow are measurably conjugate, along with some of the required background.
Sensitivity of holographic ${\cal N}=4$ SYM plasma hydrodynamics to finite coupling correctionsJul 14 2018Sep 11 2018Gauge theory/string theory holographic correspondence for ${\cal N}=4$ supersymmetric Yang-Mills theory is well under control in the planar limit, and for large (infinitely large) 't Hooft coupling, $\lambda\to \infty$. Certain aspects of the correspondence ... More
Sets in $\mathbb{R}^d$ with slow-decaying density that avoid an unbounded collection of distancesJun 02 2019Jun 05 2019For any $d\in \mathbb{N}$ and any function $f:(0,\infty)\to [0,1]$ with $f(R)\to 0$ as $R\to \infty$, we construct a set $A \subseteq \mathbb{R}^d$ and a sequence $R_n \to \infty$ such that $\|x-y\| \neq R_n$ for all $x,y\in A$ and $\mu(A\cap B_{R_n})\geq ... More
The effect of stock market indexing on corporate tax avoidanceSep 01 2015Membership in the Russell 1000 and 2000 Indices is based on a ranking of market capitalization in May. Each index is separately value weighted such that firms just inside the Russell 2000 are comparable in size to firms just outside (i.e. at the bottom ... More
The Cosmological ConstantNov 23 2012Contrary to popular mythology, Einstein did not invent the cosmological constant just in order construct his model universe. He discussed it earlier in "The Foundations of General Relativity" in connection with the proper structure of the source-free ... More
A fast analysis-based discrete Hankel transform using asymptotic expansionsJan 07 2015May 20 2015A fast and numerically stable algorithm is described for computing the discrete Hankel transform of order $0$ as well as evaluating Schl\"{o}milch and Fourier--Bessel expansions in $\mathcal{O}(N(\log N)^2/\log\!\log N)$ operations. The algorithm is based ... More
Topological AE(0)-groupsJan 04 2000We investigate topological AE(0) -groups class of which contains the class of Polish groups as well as the class of all locally compact groups. We establish the existence of an universal AE(0) -group of a given weight as well as the existence of an universal ... More
A divisorial valuation with irrational volumeJun 21 2002In this paper we present a divisorial valuation with irrational volume using an algebro-geometric construction.
Congruence classes of large configurations in vector spaces over finite fieldsJan 28 2019Bennett, Hart, Iosevich, Pakianathan, and Rudnev found an exponent $s<d$ such that any set $E\subset \mathbb{F}_q^d$ with $|E|\gtrsim q^s$ determines $\gtrsim q^{\binom{k+1}{2}}$ congruence classes of $(k+1)$-point configurations for $k\leq d$. Because ... More
On the Local Theory of Billiards in PolygonsMay 06 2014A periodic trajectory on a polygonal billiard table is stable if it persists under any sufficiently small perturbation of the table. It is a standard result that a periodic trajectory on an $n$-gon gives rise in a natural way to a closed path on an $n$-punctured ... More
Transcendental lattice of an extremal elliptic surfaceJul 10 2009Oct 01 2009We develop an algorithm computing the transcendental lattice and the Mordell--Weil group of an extremal elliptic surface. As an example, we compute the lattices of four exponentially large series of surfaces
The Bertini involutionDec 05 2012We summarize and extend E. Moody's results on the explicit equations related to the Bertini involution.
Vacuum Instability in Topologically Massive Gauge TheoryAug 12 1998We find the critical charge for a topologically massive gauge theory for any gauge group, generalising our earlier result for SU(2). The relation between critical charges in TMGT, singular vectors in the WZNW model and logarithmic CFT is investigated. ... More
Sketch2code: Generating a website from a paper mockupMay 09 2019An early stage of developing user-facing applications is creating a wireframe to layout the interface. Once a wireframe has been created it is given to a developer to implement in code. Developing boiler plate user interface code is time consuming work ... More
The binomial ideal of the intersection axiom for conditional probabilitiesFeb 09 2009Dec 04 2009The binomial ideal associated with the intersection axiom of conditional probability is shown to be radical and is expressed as intersection of toric prime ideals. This resolves a conjecture in algebraic statistics due to Cartwright and Engstr\"om.
The Non-Axiomatizability of O-MinimalityMar 13 2012Mar 29 2012Fix a language L extending the language of real closed fields by at least one new predicate or function symbol. Call an L-structure R pseudo-o-minimal if it is (elementarily equivalent to) an ultraproduct of o-minimal structures. We show that for any ... More
The Dimension of the Center of a Brauer Configuration AlgebraJul 26 2017Jul 11 2018We consider an arbitrary algebra of the class of Brauer configuration algebras and calculate the dimension of the center by determining a $K$-basis.
Positivity on subvarieties and vanishing of higher cohomologyDec 06 2010We study the relationship between positivity of line bundles restricted to complete intersection subvarieties and the vanishing of higher cohomology groups. Based on this connection we prove generalizations of the vanishing theorems of Kawamata-Viehweg ... More
On certain Cuntz-Pimsner algebrasAug 29 2001Let $A$ be a separable unital C*-algebra and let $\pi : A \ra \Lc(\Hf)$ be a faithful representation of $A$ on a separable Hilbert space $\Hf$ such that $\pi(A) \cap \Kc(\Hf) = \{0 \}$. We show that $\Oc_E$, the Cuntz-Pimsner algebra associated to the ... More
A Grauert Type Theorem and Extension of Matrices with Entries in H^{\infty}Dec 15 2001In the paper we prove an extension theorem for matrices with entries in H^{\infty}(U) for U being a Riemann surface of a special type. One of the main components of the proof is a Grauert type theorem for "holomorphic" vector bundles defined over maximal ... More
Lines generate the Picard groups of certain Fermat surfacesMay 14 2013Jun 05 2014We answer a question of T.Shioda and show that, for any positive integer $m$ prime to 6, the Picard group of the Fermat surface $\Phi_m$ is generated by the classes of lines contained in $\Phi_m$.
Volumes of line bundlesNov 26 2002Dec 10 2003This paper has been removed by the author due to a misstatement in Theorem 1 and a gap in its proof. A corrected and largely extended successor (a joint work with Thomas Bauer and Tomasz Szemberg) can be found under math.AG/0312211,
Levels of Distribution and the Affine SieveJun 05 2014This article is an expanded version of the author's lecture in the Basic Notions Seminar at Harvard, September 2013. Our goal is a brief and introductory exposition of aspects of two topics in sieve theory which have received attention recently: (1) the ... More
On H-closed paratopological groupsMar 28 2010A Hausdorff paratopological group G is H-closed if G is closed in each Hausdorff paratopological group containing G. We obtain criteria of H-closedness for some classes of abelian paratopological groups. In particular, for topological groups.
A New Definition of the Steenrod Operations in Algebraic GeometryMay 09 2008The Steenrod operations (mod p) in Chow theory are defined for any prime p for a quasi-projective scheme, without appealing to the results of any domain but Milnor's K-theory. The new definition also gives a direct formula that depends only on the scheme ... More
Universal C*-algebra of real rank zeroNov 26 1999Apr 16 2000It is well-known that every commutative separable unital C*-algebra of real rank zero is a quotient of the C*-algebra of all compex continous functions defined on the Cantor cube. We prove a non-commutative version of this result by showing that the class ... More
Uncountable direct systems and a characterization of non-separable projective $C^{\ast}$-algebrasAug 15 1999We introduce the concept of a direct $C_{\omega}^{\ast}$-system and show that every non-separable unital $C^{\ast}$-algebra is the limit of essentially unique direct $C_{\omega}^{\ast}$-system. This result is then applied to the problem of characterization ... More
Finite approximations of $p$-local compact groupsMar 30 2015Dec 08 2015We show that the classifying space of a $p$-local compact group is approximated by a telescope of classifying spaces of $p$-local finite groups. This result has numerous implications, like a Stable Elements Theorem for $p$-local compact groups, or the ... More
Classical Zariski pairsJul 10 2009We compute the fundamental groups of all irreducible plane sextics constituting classical Zariski pairs
Plane sextics with a type $\bold E_8$ singular pointFeb 13 2009We construct explicit geometric models for and compute the fundamental groups of all plane sextics with simple singularities only and with at least one type $\bold E_8$ singular point. In particular, we discover four new sextics with nonabelian fundamental ... More
KP Solitons are BispectralSep 07 1998It is by now well known that the wave functions of rational solutions to the KP hierarchy which can be achieved as limits of the pure $n$-soliton solutions satisfy an eigenvalue equation for ordinary differential operators in the spectral parameter. This ... More
Generalized varieties of sums of powersJan 09 2014Let $X\subset\mathbb{P}^{N}$ be an irreducible, non-degenerate variety. The generalized variety of sums of powers $VSP_H^X(h)$ of $X$ is the closure in the Hilbert scheme $Hilb_{h}(X)$ of the locus parametrizing collections of points $\{x_{1},...,x_{h}\}$ ... More
Z-set unknotting in uncountable products of realsFeb 08 2011We prove a version of $Z$-set unknotting theorem for uncountable products of real numbers.
Oka's conjecture on irreducible plane sexticsJan 24 2007Apr 17 2008We partially prove and partially disprove Oka's conjecture on the fundamental group/Alexander polynomial of an irreducible plane sextic. Among other results, we enumerate all irreducible sextics with simple singularities admitting dihedral coverings and ... More
From Apollonius To Zaremba: Local-Global Phenomena in Thin OrbitsAug 27 2012We discuss a number of naturally arising problems in arithmetic, culled from completely unrelated sources, which turn out to have a common formulation involving "thin" orbits. These include the local-global problem for integral Apollonian gaskets and ... More
Outer automorphism groups of some ergodic equivalence relationsDec 17 2003Let R a be countable ergodic equivalence relation of type II_1 on a standard probability space (X,m). The group Out(R) of outer automorphisms of R consists of all invertible Borel measure preserving maps of the space which map R-classes to R-classes modulo ... More
Rational Growth in Virtually Abelian GroupsAug 20 2018We show that any subgroup of a finitely generated virtually abelian group $G$ grows rationally relative to $G$, that the set of right cosets of any subgroup of $G$ grows rationally, and that the set of conjugacy classes of $G$ grows rationally. These ... More
Irreducible $p$-local compact groups I. The structure of $p$-local compact groups of rank $1$Dec 18 2013Jan 23 2014Let $p$ be a fixed prime number. The main purpose of this paper is to introduce the notion of \textit{irreducible} $p$-local compact group, which provides a first reduction towards a classification of all $p$-local compact groups. In order to test this ... More
On the biregular geometry of the Fulton-MacPherson compactificationMar 22 2016Oct 11 2017Let $X[n]$ be the Fulton-MacPherson compactification of the configuration space of $n$ ordered points on a smooth projective variety $X$. We prove that if either $n\neq 2$ or $\dim(X)\geq 2$, then the connected component of the identity of $Aut(X[n])$ ... More
On Setting of Heat-and-Mass Transfer Problems under Directed CrystallizationAug 11 2011So far the problem of interface behavior upon phase transition has not yet acquired a satisfactory mathematical formulation due to a variety of the physical phenomena involved. Analytical solutions exist only for elementary problems describing the free ... More
Numerical homotopy continuation for control and online identification of nonlinear systems: the survey of selected resultsJan 26 2013The article gives an overview of the parameter numerical continuation methodology applied to setpoint control and parameter identification of nonlinear systems. The control problems for affine systems as well as general (nonaffine) nonlinear systems are ... More
The Negative Cycle Vectors of Signed Complete GraphsDec 30 2015A signed graph is a graph where the edges are assigned labels of either "$+$" or "$-$". The sign of a cycle in the graph is the product of the signs of its edges. We equip each signed complete graph with a vector whose entries are the number of negative ... More
Stochastic Backpropagation through Mixture Density DistributionsJul 19 2016The ability to backpropagate stochastic gradients through continuous latent distributions has been crucial to the emergence of variational autoencoders and stochastic gradient variational Bayes. The key ingredient is an unbiased and low-variance way of ... More
The probability of finding a fixed pattern in random data depends monotonically on the bifix indicatorJul 30 2012We consider the problem of finding a fixed L-ary sequence in a stream of random L-ary data. It is known that the expected search time is a strictly increasing function of the lengths of the bifices of the pattern. In this paper we prove the related statement ... More
The Local-Global Principle for Integral Soddy Sphere PackingsAug 27 2012Fix an integral Soddy sphere packing P. Let K be the set of all curvatures in P. A number n is called represented if n is in K, that is, if there is a sphere in P with curvature equal to n. A number n is called admissible if it is everywhere locally represented, ... More
Duality symmetry of BFKL equation: reggeized gluons vs color dipolesNov 27 2009We show that the duality symmetry of the BFKL equation can be interpreted as a symmetry under rotation of the BFKL Kernel in the transverse space from s-channel (color dipole model) to t-channel (reggeized gluon formulation). We argue that the duality ... More
Integer Lattice Gases at EquilibriumDec 14 2005Jan 24 2006Integer lattice gas automata can be utilized as building blocks in statistical mechanics. The presented deterministic and reversible automaton generates semiclassical statistical distributions. A possible approach to Bose-Einstein statistics from cellular ... More
Smooth models of singular $K3$-surfacesAug 24 2016Sep 05 2016We show that the classical Fermat quartic has exactly three smooth spatial models. As a generalization, we give a classification of smooth spatial (as well as some other) models of singular $K3$-surfaces of small discriminant. As a by-product, we observe ... More
On (Non)Supermodularity of Average Control EnergySep 27 2016Given a linear system, we consider the expected energy to move from the origin to a uniformly random point on the unit sphere as a function of the set of actuated variables. We show this function is not necessarily supermodular, correcting some claims ... More
A model-insensitive determination of First-hitting-time densities with Application to Equity default-swapsFeb 12 2010Mar 29 2010Equity default-swaps pay the holder a fixed amount of money when the underlying spot level touches a (far-down) barrier during the life of the instrument. While most pricing models give reasonable results when the barrier lies within the range of liquidly ... More
Critical phenomena in N=4 SYM plasmaMay 05 2010Strongly coupled N=4 supersymmetric Yang-Mills plasma at finite temperature and chemical potential for an R-symmetry charge undergoes a second order phase transition. We demonstrate that this phase transition is of the mean field theory type. We explicitly ... More
Gauge theories on hyperbolic spaces and dual wormhole instabilitiesFeb 21 2004Jul 26 2004We study supergravity duals of strongly coupled four dimensional gauge theories formulated on compact quotients of hyperbolic spaces. The resulting background geometries are represented by Euclidean wormholes, which complicates establishing the precise ... More
Compactifications of the N=2^* flowFeb 14 2003In hep-th/0004063 Pilch and Warner (PW) constructed N=2 supersymmetric RG flow corresponding to the mass deformation of the N=4 SU(N) Yang-Mills theory. In this paper we present exact deformations of PW flow when the gauge theory 3-space is compactified ... More
Finite temperature resolution of the Klebanov-Tseytlin singularityNov 16 2000Feb 19 2001Naked singularities in the gravitational backgrounds dual to gauge theories can be hidden behind the black hole horizon. We present an exact black hole solution in the Klebanov-Tseytlin geometry [hep-th/0002159]. Our solution realizes Maldacena dual of ... More