Results for "Andrea Turrini"

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Cost Preserving Bisimulations for Probabilistic AutomataOct 30 2014Feb 16 2015Probabilistic automata constitute a versatile and elegant model for concurrent probabilistic systems. They are equipped with a compositional theory supporting abstraction, enabled by weak probabilistic bisimulation serving as the reference notion for ... More
Deciding Probabilistic Automata Weak Bisimulation in Polynomial TimeMay 02 2012Jul 15 2012Deciding in an efficient way weak probabilistic bisimulation in the context of Probabilistic Automata is an open problem for about a decade. In this work we close this problem by proposing a procedure that checks in polynomial time the existence of a ... More
Anti-correlation between multiplicity and orbital properties in exoplanetary systems as a possible record of their dynamical historiesAug 31 2017Previous works focused on exoplanets discovered with the radial velocity (RV) method reported an anti-correlation between the orbital eccentricities of the exoplanets and the multiplicity M (i.e., number of planets) of their system. We further investigate ... More
Compositional Reasoning for Interval Markov Decision ProcessesJul 28 2016Model checking probabilistic CTL properties of Markov decision processes with convex uncertainties has been recently investigated by Puggelli et al. Such model checking algorithms typically suffer from the state space explosion. In this paper, we address ... More
Synthesising Strategy Improvement and Recursive Algorithms for Solving 2.5 Player Parity GamesJul 06 20162.5 player parity games combine the challenges posed by 2.5 player reachability games and the qualitative analysis of parity games. These two types of problems are best approached with different types of algorithms: strategy improvement algorithms for ... More
Model Checking Applied to Quantum PhysicsFeb 08 2019Model checking has been successfully applied to verification of computer hardware and software, communication systems and even biological systems. In this paper, we further push the boundary of its applications and show that it can be adapted for applications ... More
Planetesimals and Satellitesimals: Formation of the Satellite SystemsJun 01 2009Dec 14 2009The origin of the regular satellites ties directly to planetary formation in that the satellites form in gas and dust disks around the giant planets and may be viewed as mini-solar systems, involving a number of closely related underlying physical processes. ... More
The primordial collisional history of Vesta: crater saturation, surface evolution and survival of the basaltic crustSep 05 2013This work explores the implications of the Jovian Early Bombardment (JEB) for the evolution of the primordial Vesta, in particular in terms of crater saturation, crustal excavation and surface erosion. Both scenarios assuming the planetesimals having ... More
An Efficient Synthesis Algorithm for Parametric Markov Chains Against Linear Time PropertiesMay 14 2016In this paper, we propose an efficient algorithm for the parameter synthesis of PLTL formulas with respect to parametric Markov chains. The PLTL formula is translated to an almost fully partitioned B\"uchi automaton which is then composed with the parametric ... More
Vesta and Ceres: crossing the history of the Solar SystemJun 01 2011The evolution of the Solar System can be schematically divided into three different phases: the Solar Nebula, the Primordial Solar System and the Modern Solar System. These three periods were characterized by very different conditions, both from the point ... More
Computing rational decisions in extensive games with limited foresightFeb 12 2015May 29 2016We introduce a class of extensive form games where players might not be able to foresee the possible consequences of their decisions and form a model of their opponents which they exploit to achieve a more profitable outcome. We improve upon existing ... More
Lazy Probabilistic Model Checking without DeterminisationNov 12 2013Apr 24 2015The bottleneck in the quantitative analysis of Markov chains and Markov decision processes against specifications given in LTL or as some form of nondeterministic B\"uchi automata is the inclusion of a determinisation step of the automaton under consideration. ... More
Endogenous games with goals: side-payments among goal-directed artificial agentsNov 13 2013Nov 14 2013Artificial agents are typically oriented to the realization of an externally assigned task and try to optimize over secondary aspects of plan execution such time lapse or power consumption, technically displaying a quasi-dichotomous preference relation. ... More
The Formation of Jupiter, the Jovian Early Bombardment and the Delivery of Water to the Asteroid Belt: The Case of (4) VestaJan 29 2014The asteroid (4) Vesta, parent body of the Howardite-Eucrite-Diogenite meteorites, is one of the first bodies that formed, mostly from volatile-depleted material, in the Solar System. The Dawn mission recently provided evidence that hydrated material ... More
Asteroid 4 Vesta: dynamical and collisional evolution during the Late Heavy BombardmentFeb 01 2016Aug 23 2016Vesta is the only currently identified asteroid for which we possess samples, which revealed us that the asteroid is differentiated and possesses a relatively thin basaltic crust that survived to the evolution of the asteroid belt and the Solar System. ... More
The Influence of Space Environment on the Evolution of MercuryMay 28 2014Mercury, due to its close location to the Sun, is surrounded by an environment whose conditions may be considered as "extreme" in the entire Solar System. Both solar wind and radiation are stronger with respect to other Solar System bodies, so that their ... More
Two-player preplay negotiation games with conditional offersApr 08 2013Nov 18 2013We consider an extension of strategic normal form games with a phase before the actual play of the game, where players can make binding offers for transfer of utilities to other players after the play of the game, contingent on the recipient playing the ... More
Non-cooperative games with preplay negotiationsAug 08 2012Nov 18 2013We consider an extension of strategic normal form games with a phase of negotiations before the actual play of the game, where players can make binding offers for transfer of utilities to other players after the play of the game, in order to provide additional ... More
A network-based rating system and its resistance to briberyFeb 03 2016Jun 27 2016We study a rating system in which a set of individuals (e.g., the customers of a restaurant) evaluate a given service (e.g, the restaurant), with their aggregated opinion determining the probability of all individuals to use the service and thus its generated ... More
A new perspective on the irregular satellites of Saturn - I Dynamical and collisional historyNov 25 2010The dynamical features of the irregular satellites of the giant planets argue against an in-situ formation and are strongly suggestive of a capture origin. Since the last detailed investigations of their dynamics, the total number of satellites have doubled, ... More
Classification of smooth congruences with a fundamental curveJun 23 1993We give a classification and a construction of all smooth $(n-1)$-dimensional varieties of lines in ${\bf P}\sp n$ verifying that all their lines meet a curve. This also gives a complete classification of $(n-1)$-scrolls over a curve contained in $G(1,n)$. ... More
From gas to satellitesimals: disk formation and evolutionJun 18 2009Nov 18 2009The subject of satellite formation is strictly linked to the one of planetary formation. Giant planets strongly shape the evolution of the circum-planetary disks during their formation and thus, indirectly, influence the initial conditions for the processes ... More
A focus on focal surfacesFeb 14 2000We make a systematic study of the focal surface of a congruence of lines in the projective space. Using differential techniques together with techniques from intersection theory, we reobtain in particular all the invariants of the focal surface (degree, ... More
Equilibrium Refinement through Negotiation in Binary VotingApr 22 2014Jul 14 2015We study voting games on binary issues, where voters might hold an objective over some issues at stake, while willing to strike deals on the remaining ones, and can influence one another's voting decision before the vote takes place. We analyse voters' ... More
Probing the history of Solar System through the cratering records on Vesta and CeresFeb 20 2009Jan 10 2011Through its connection with HED meteorites, Vesta is known as one of the first bodies to have accreted and differentiated in the Solar Nebula, predating the formation of Jupiter and surviving the violent evolution of the early Solar System. The formation ... More
The role of planetary formation and evolution in shaping the composition of exoplanetary atmospheresJan 20 2014Jun 16 2014Over the last twenty years, the search for extrasolar planets revealed us the rich diversity of the outcomes of the formation and evolution of planetary systems. In order to fully understand how these extrasolar planets came to be, however, the orbital ... More
A new perspective on the irregular satellites of Saturn - II Dynamical and physical originNov 25 2010The origin of the irregular satellites of the giant planets has been long debated since their discovery. Their dynamical features argue against an in-situ formation suggesting they are captured bodies, yet there is no global consensus on the physical ... More
Jovian Early Bombardment: planetesimal erosion in the inner asteroid beltFeb 22 2012The asteroid belt is an open window on the history of the Solar System, as it preserves records of both its formation process and its secular evolution. The progenitors of the present-day asteroids formed in the Solar Nebula almost contemporary to the ... More
Status of sub-GeV Hidden Particle SearchesAug 26 2010Hidden sector particles with sub-GeV masses like hidden U(1) gauge bosons, the NMSSM CP-odd Higgs, and other axion-like particles are experimentally little constrained as they interact only very weakly with the visible sector. For masses below the muon ... More
The electroweak chiral Lagrangian reanalyzedJul 09 1999Oct 26 2000In this paper we reanalyze the electroweak chiral Lagrangian with particular focus on two issues related to gauge invariance. Our analysis is based on a manifestly gauge-invariant approach that we introduced recently. It deals with gauge-invariant Green's ... More
A universal ionization threshold for strongly driven Rydberg statesApr 21 2004We observe a universal ionization threshold for microwave driven one-electron Rydberg states of H, Li, Na, and Rb, in an {\em ab initio} numerical treatment without adjustable parameters. This sheds new light on old experimental data, and widens the scene ... More
Residual Symmetries in the Spectrum of Periodically Driven Alkali Rydberg StatesNov 25 1999We identify a fundamental structure in the spectrum of microwave driven alkali Rydberg states, which highlights the remnants of the Coulomb symmetry in the presence of a non-hydrogenic core. Core-induced corrections with respect to the hydrogen spectrum ... More
Lipschitz functions with prescribed blowups at many pointsDec 15 2016In this paper we prove generalizations of Lusin-type theorems for gradients due to Giovanni Alberti, where we replace the Lebesgue measure with any Radon measure $\mu$. We apply this to go beyond the known result on the existence of Lipschitz functions ... More
A Multilevel Monte Carlo Algorithm for Parabolic Advection-Diffusion Problems with Discontinuous CoefficientsFeb 06 2019The Richards' equation is a model for flow of water in unsaturated soils. The coefficients of this (nonlinear) partial differential equation describe the permeability of the medium. Insufficient or uncertain measurements are commonly modeled by random ... More
Planetary formation in the Gamma-Cephei systemAug 09 2004We numerically investigate under which conditions the planet detected at 2.1 AU of Gamma-Cephei could form through the core-accretion scenario despite the perturbing presence of the highly eccentric companion star. We first show that the initial stage ... More
Band-edge BCS-BEC crossover in a two-band superconductor: physical properties and detection parametersJul 11 2014Superconductivity in iron-based, magnesium diborides, and other novel superconducting materials has a strong multi-band and multi-gap character. Recent experiments support the possibillity for a BCS-BEC crossover induced by strong-coupling and proximity ... More
Thermodynamic properties and thermal correlation lengths of a Hubbard model with bond-charge interactionFeb 27 2004We investigate the thermodynamics of a one-dimensional Hubbard model with bond-charge interaction X using the transfer matrix renormalization group method (TMRG). Numerical results for various quantities like spin and charge susceptibilities, particle ... More
Imbalanced thee-component Fermi gas with attractive interactions: Multiple FFLO-pairing, Bose-Fermi and Fermi-Fermi mixtures versus collapse and phase separationJun 04 2009We present a detailed study of the population imbalanced three-component Hubbard chain with attractive interactions. Such a system can be realized experimentally with three different hyperfine states of ultra cold $^6$Li atoms in an optical lattice. We ... More
Classification of maximal transitive prolongations of super-Poincaré algebrasDec 08 2012Jul 22 2014Let $V$ be a complex vector space with a non-degenerate symmetric bilinear form and $\mathbb S$ an irreducible module over the Clifford algebra $Cl(V)$ determined by this form. A supertranslation algebra is a $\mathbb Z$-graded Lie superalgebra $\mathfrak ... More
Super-Poincare' algebras, space-times and supergravities (II)Aug 31 2011The presentation of supergravity theories of our previous paper "Super-Poincare' algebras, space-times and supergravities (I)" is re-formulated in the language of Berezin-Leites-Kostant theory of supermanifolds. It is also shown that the equations of ... More
Equivariant characteristic forms in the Cartan model and Borel equivariant cohomologyAug 31 2015Nov 10 2015We show the compatibility of the differential geometric and the topological construction of equivariant characteristic classes for compact Lie groups. Our analysis motivates a differential geometric construction for equivariant characteristic classes ... More
Numerical analysis for time-dependent advection-diffusion problems with random discontinuous coefficientsFeb 06 2019Subsurface flows are commonly modeled by advection-diffusion equations. Insufficient measurements or uncertain material procurement may be accounted for by random coefficients. To represent, for example, transitions in heterogeneous media, the parameters ... More
Gauge-invariant Green's functions for the bosonic sector of the standard modelDec 18 1998Jun 21 2000There are many applications in gauge theories where the usually employed framework involving gauge-dependent Green's functions leads to considerable problems. In order to overcome the difficulties invariably tied to gauge dependence, we present a manifestly ... More
Equivariant Differential CohomologyOct 21 2015Nov 10 2015The construction of characteristic classes via the curvature form of a connection is one motivation for the refinement of integral cohomology by de Rham cocycles -- known as differential cohomology. We will discuss the analog in the case of a group action ... More
The antiferromagnetic spin-1/2 Heisenberg model on the square lattice in a magnetic fieldDec 17 2008Mar 16 2009We study the field dependence of the antiferromagnetic spin-1/2 Heisenberg model on the square lattice by means of exact diagonalizations. In a first part, we calculate the spin-wave velocity, the spin-stiffness, and the magnetic susceptibility and thus ... More
Solving DC programs with polyhedral component utilizing a multiple objective linear programming solverOct 18 2016A class of non-convex optimization problems with DC objective function and linear constraints is studied, where DC stands for being representable as the difference $f=g-h$ of two convex functions $g$ and $h$. In particular, we deal with the special case ... More
(a,b)-Koszul algebrasJul 20 2010Let $a$ and $b$ be two integers such that $2\le a<b$. In this article we define the notion of $(a,b)$-Koszul algebra as a generalization of $N$-Koszul algebras. We also exhibit examples and we provide a minimal graded projective resolution of the algebra ... More
PT-symmetrically deformed shock wavesJan 27 2012We investigate for a large class of nonlinear wave equations, which allow for shock wave formations, how these solutions behave when they are PT-symmetrically deformed. For real solutions we find that they are transformed into peaked solutions with a ... More
Numerical analysis of detection-mechanism models of SNSPDAug 27 2013Nov 12 2013The microscopic mechanism of photon detection in superconducting nanowire single-photon detectors is still under debate. We present a simple, but powerful theoretical model that allows us to identify essential differences between competing detection mechanisms. ... More
The Comparative Exploration of the Ice Giant Planets with Twin Spacecraft: Unveiling the History of our Solar SystemFeb 11 2014Sep 11 2014In the course of the selection of the scientific themes for the second and third L-class missions of the Cosmic Vision 2015-2025 program of the European Space Agency, the exploration of the ice giant planets Uranus and Neptune was defined "a timely milestone, ... More
The ODINUS Mission Concept - The Scientific Case for a Mission to the Ice Giant Planets with Twin Spacecraft to Unveil the History of our Solar SystemFeb 11 2014Feb 12 2014The purpose of this document is to discuss the scientific case of a space mission to the ice giants Uranus and Neptune and their satellite systems and its relevance to advance our understanding of the ancient past of the Solar System and, more generally, ... More
Olivine on Vesta as exogenous contaminants brought by impacts: Constraints from modeling Vesta's collisional history and from impact simulationsJul 25 2016Jul 28 2016The survival of asteroid Vesta during the violent early history of the Solar System is a pivotal constraint on theories of planetary formation. Particularly important from this perspective is the amount of olivine excavated from the vestan mantle by impacts, ... More
Unrectifiable normal currents in Euclidean spacesAug 04 2016We construct in $\mathbb{R}^{k+2}$ a $k$-dimensional simple normal current whose support is purely $2$-unrectifiable. The result is sharp because the support of a normal current cannot be purely $1$-unrectifiable and a $(k+1)$-dimensional normal current ... More
A Mathematical Theory of Co-DesignDec 25 2015Oct 05 2016This paper describes a theory of "co-design", in which the objects of investigation are "design problems", defined as tuples of "functionality space", "implementation space", and "resources space", together with a feasibility relation that relates the ... More
Torsion group schemes as iterative differential Galois groupsMar 28 2012Oct 14 2015We are considering iterative derivations on the function field L of abelian schemes in positive characteristic p>0, and give conditions when the torsion group schemes of this abelian scheme occur as ID-automorphism groups, i.e. are the ID-Galois groups ... More
Infinitesimal group schemes as iterative differential Galois groupsAug 26 2009This article is concerned with Galois theory for iterative differential fields (ID-fields) in positive characteristic. More precisely, we consider purely inseparable Picard-Vessiot extensions, because these are the ones having an infinitesimal group scheme ... More
The Nagel-Schreckenberg model revisitedFeb 11 1999The Nagel-Schreckenberg model is a simple cellular automaton for a realistic description of single-lane traffic on highways. For the case $v_{max}=1$ the properties of the stationary state can be obtained exactly. For the more relevant case $v_{max}>1$, ... More
Anomalous U(1), Dark Matter and AsymmetryJan 20 2012Jun 14 2012In this thesis we study the phenomenology of an anomalous U(1) extension of the MSSM. We briefly introduce the concept of Supersymmetry and describe the MSSM, then we introduce our extended model, describing its main properties. Then it starts the original ... More
An Information-Based Framework for Asset Pricing: X-Factor Theory and its ApplicationsJul 14 2008A new framework for asset pricing based on modelling the information available to market participants is presented. Each asset is characterised by the cash flows it generates. Each cash flow is expressed as a function of one or more independent random ... More
Entire functions sharing simple $a$-points with their first derivative IINov 11 2014We discuss some results around the following question: Let $f$ be a nonconstant complex entire function and $a$, $b$ two distinct complex numbers. If $f$ and its derivative $f'$ share their simple $a$-points and also share the value $b$, does this imply ... More
Field Parametrization Dependence in Asymptotically Safe Quantum GravityOct 28 2014Jan 26 2015Motivated by conformal field theory studies we investigate Quantum Einstein Gravity with a new field parametrization where the dynamical metric is basically given by the exponential of a matrix-valued fluctuating field, $g_{\mu\nu}=\bar{g}_{\mu\rho}(e^h)^\rho_{\nu}$. ... More
A Measurement of the UHECR Spectrum with the HiRes FADC DetectorSep 06 2004We have measured the energy spectrum of ultra-high energy cosmic rays (UHECR) with the HiRes FADC detector (HiRes-2) in monocular mode. A detailed Monte Carlo simulation of the detector response to air showers has been used to calculate the energy dependent ... More
The Abelian Embedding Formulation of the Stueckelberg Model and its Power-counting Renormalizable ExtensionJan 23 2006We elucidate the geometry of the polynomial formulation of the non-abelian Stueckelberg mechanism. We show that a natural off-shell nilpotent BRST differential exists allowing to implement the constraint on the sigma field by means of BRST techniques. ... More
Canonical Flow in the Space of Gauge ParametersDec 21 2014Gauge dependence of one-particle irreducible (1-PI) amplitudes in SU(N) Yang-Mills theory is shown to be generated by a canonical flow with respect to (w.r.t.) the extended Slavnov-Taylor (ST) identity, induced by the transformation of the gauge parameter ... More
Non-trivial Backgrounds in (non-perturbative) Yang-Mills Theory by the Slavnov-Taylor IdentityNov 28 2011Dec 08 2011We show that in the background field method (BFM) quantization of Yang-Mills theory the dependence of the vertex functional on the background field is controlled by a canonical transformation w.r.t. the Batalin-Vilkovisky bracket, naturally associated ... More
Gravitino phenomenology and cosmological implications of supergravityFeb 15 2010Gravitino production in the primordial Universe is investigated into details. After briefly reviewing inflation, supersymmetry and supergravity, we first study the scattering of massive W bosons in the thermal bath of particles, during the period of reheating. ... More
Symmetries, higher order symmetries and supersymmetriesFeb 12 2010Mar 16 2012We discuss a geometrical formulation for gauge field theories, called Gauge-Natural, which has been mostly developed at the University of Turin (Italy) and at the Masaryk University in Brno (Czech Republic). In this framework, the group of automorphisms ... More
Die Gerling Sternwarte (Gerling Astronomical Observatory)Mar 13 2015Christian Ludwig Gerling's 1817 appointment as Professor for Mathematics, Physics and Astronomy resulted in the foundation of the Mathematical and Physical Institute of the Philipps University. In 1838, Gerling moved onto new premises in the main building ... More
Quantum chaos inside Black HolesAug 07 2015Oct 21 2015We show how semiclassical black holes can be reinterpreted as an effective geometry, composed of a large ensamble of horizonless naked singularities (eventually smoothed at the Planck scale). We call this new items {\it frizzyballs}, which can be rigorously ... More
Some Remarks on the Logic of Quantum GravityJun 13 2013We discuss some conceptual issues that any approach to quantum gravity has to confront. In particular, it is argued that one has to find a theory that can be interpreted in a realist manner, because theories with an instrumentalist interpretation are ... More
Topos theory and `neo-realist' quantum theoryDec 24 2007Topos theory, a branch of category theory, has been proposed as mathematical basis for the formulation of physical theories. In this article, we give a brief introduction to this approach, emphasising the logical aspects. Each topos serves as a `mathematical ... More
Observables as functions: Antonymous functionsOct 13 2005Antonymous functions are real-valued functions on the Stone spectrum of a von Neumann algebra R. They correspond to the self-adjoint operators in R, which are interpreted as observables in quantum physics. Antonymous functions turn out to be generalized ... More
Kochen-Specker theorem for von Neumann algebrasAug 16 2004The Kochen-Specker theorem has been discussed intensely ever since its original proof in 1967. It is one of the central no-go theorems of quantum theory, showing the non-existence of a certain kind of hidden states models. In this paper, we first offer ... More
Equations for two-phase flows: a primerJan 29 2011The main goal of these notes is to give a review of the equations for two phase flow problems with an interface between the two phases in a self-contained way, and, in particular, to properly include surface tension into the interface balance equations. ... More
Self-Interacting Cold Dark Matter HalosDec 08 2000The evolution of halos consisting of weakly self-interacting dark matter particles is summarized. The halos initially contain a central density cusp as predicted by cosmological models. Weak self-interaction leads to the formation of an isothermal, low-density ... More
The structure and evolution of weakly self-interacting cold dark matter halosFeb 22 2000Apr 18 2000The evolution of halos consisting of weakly self-interacting dark matter particles is investigated using a new numerical Monte-Carlo N-body method. The halos initially contain kinematically cold, dense 1/r-power-law cores. For interaction cross sections ... More
Galactic Disk Formation and the Angular Momentum ProblemAug 10 2009Galactic disk formation requires knowledge about the initial conditions under which disk galaxies form, the boundary conditions that affect their secular evolution and the micro-physical processes that drive the multi-phase interstellar medium and regulate ... More
Stellar Feedback Processes: Their Impact on Star Formation and Galactic EvolutionApr 01 2004The conditions that lead to self-regulated star formation, star bursts and the formation of massive stellar clusters are discussed. Massive stars have a strong impact on their environment, especially on the evolution of dwarf galaxies which are the building ... More
The Formation of the Milky Way in the Cosmological ContextMay 17 2001The formation of the Milky Way is discussed within the context of the cold dark matter scenario. Several problems arise which can be solved if the Galaxy experienced an early phase of gas heating and decoupling from the dark matter substructure. This ... More
Results from NA57Sep 30 2005The NA57 experiment has measured the production of strange and multi-strange hadrons in heavy-ion collisions at the CERN SPS. After briefly introducing the NA57 apparatus and analysis procedures, we present recent results on strangeness enhancement in ... More
Virtual TexturingMay 18 2010In this thesis a rendering system and an accompanying tool chain for Virtual Texturing is presented. Our tools allow to automatically retexture existing geometry in order to apply unique texturing on each face. Furthermore we investigate several techniques ... More
Irrelevance of memory in the minority gameDec 13 1998By means of extensive numerical simulations we show that all the distinctive features of the minority game introduced by Challet and Zhang (1997), are completely independent from the memory of the agents. The only crucial requirement is that all the individuals ... More
Closures in $\aleph_0$-categorical bilinear mapsJan 19 1997Alternating bilinear maps with few relations allow to define a combinatorial closure similarly as in [2]. For the $\aleph_0$-categorical case we show that this closure is part of the algebraic closure.
Functional Categories of Support to Operations in Military Information SystemsNov 30 2010In order to group the functional requirements for support to operations by modern information systems systematically, the NATO Code of best Practise (COBP) for C2 Assessment defines three domain areas: Battlespace Visualization, Decision Making, and Battle ... More
LIBOR Interpolation and the HJM ModelAug 29 2011Jun 05 2012We follow the lines of Musiela and Rutkowski and extend their interpolation method to models with jumps. Together with an extension method for the tenor structure of a given LIBOR market model (LMM) we get an infinite LIBOR termstructure. Furthermore ... More
Sustainable Credit And Interest RatesNov 13 2011Jun 07 2012With negative growth in real production in many countries and debt levels which become an increasing burden on developed societies, the calls for a change in economic policy and even the monetary system become louder and increasingly impatient. We research ... More
A non-CLP-compact product space whose finite subproducts are CLP-compactMay 11 2010Dec 04 2011We construct a family of Hausdorff spaces such that every finite product of spaces in the family (possibly with repetitions) is CLP-compact, while the product of all spaces in the family is non-CLP-compact. Our example will yield a single Hausdorff space ... More
Electromagnetism in terms of quantum measurementsSep 16 2015We consider the question whether electromagnetism can be derived from quantum physics of measurements. It turns out that this is possible, both for quantum and classical electromagnetism, if we use more recent innovations such as smearing of observables ... More
The M_BH - T relation for a black hole in thermodynamic equilibrium with the surrounding intergalactic mediumJan 19 2006I consider a toy model of self-regulated black hole accretion. The black hole grows through Bondi accretion and a fraction of the accretion power is distributed as thermal feedback into the surrounding gas. The gas expands or contracts until AGN heating ... More
Scalar functions for wave extraction in numerical relativityJan 31 2007May 30 2007Wave extraction plays a fundamental role in the binary black hole simulations currently performed in numerical relativity. Having a well defined procedure for wave extraction, which matches simplicity with efficiency, is critical especially when comparing ... More
|Vcb| and |Vub| from CLEOMay 26 2003May 26 2003I report on studies of inclusive and exclusive semileptonic b -> c l nu and b -> u l nu decays in 9.7 million BBbar events accumulated with the CLEO detector in symmetric e^+e^- collisions produced in the Cornell Electron Storage Ring (CESR). Various ... More
Lie algebroids, non-associative structures and non-geometric fluxesSep 23 2013In the first part of this article, the geometry of Lie algebroids as well as the Moyal-Weyl star product and some of its generalizations in open string theory are reviewed. A brief introduction to T-duality and non-geometric fluxes is given. Based on ... More
Reductions Between Cardinal Characteristics of the ContinuumJul 12 1994We discuss two general aspects of the theory of cardinal characteristics of the continuum, especially of proofs of inequalities between such characteristics. The first aspect is to express the essential content of these proofs in a way that makes sense ... More
Questions and answers -- a category arising in linear logic, complexity theory, and set theorySep 16 1993A category used by de Paiva to model linear logic also occurs in Vojtas's analysis of cardinal characteristics of the continuum. Its morphisms have been used in describing reductions between search problems in complexity theory. We describe this category ... More
Ultrafilters: Where topological dynamics = algebra = combinatoricsSep 08 1993We survey some connections between topological dynamics, semigroups of ultrafilters, and combinatorics. As an application, we give a proof, based on ideas of Bergelson and Hindman, of the Hales-Jewett partition theorem.
Small Connections are cyclicJul 14 2014The main local invariants of a (one variable) differential module over the complex numbers are given by means of a cyclic basis. In the $p$-adic setting the existence of a cyclic vector is often unknown. We investigate the existence of such a cyclic vector ... More
An algorithm computing non solvable spectral radii of $p$-adic differential equationsJan 07 2013We obtain an algorithm computing explicitly the values of the non solvable spectral radii of convergence of the solutions of a differential module over a point of type 2, 3 or 4 of the Berkovich affine line.
AGN models for the X and gamma-ray backgroundsDec 16 1998The origin of the X-ray background spectral intensity has been a long standing problem in high energy astrophysics research. Deep X-ray surveys carried out with ROSAT and ASCA combined with the broad band spectral results of Ginga and BeppoSAX satellites ... More
Topos-Based Logic for Quantum Systems and Bi-Heyting AlgebrasFeb 13 2012Dec 05 2013To each quantum system, described by a von Neumann algebra of physical quantities, we associate a complete bi-Heyting algebra. The elements of this algebra represent contextualised propositions about the values of the physical quantities of the quantum ... More
Walking through a library remotely - Why we need maps for collections and how KnoweScape can help us to make them?Jan 20 2015There is no escape from the expansion of information, so that structuring and locating meaningful knowledge becomes ever more difficult. The question of how to order our knowledge is as old as the systematic acquisition, circulation, and storage of knowledge. ... More