220 research outputs found
F-structures and integral points on semiabelian varieties over finite fields
Motivated by the problem of determining the structure of integral points on
subvarieties of semiabelian varieties defined over finite fields, we prove a
quantifier elimination result for certain modules over finite simple extensions
of the integers given together with predicates for orbits of the distinguished
generator of the ring.Comment: 33 pages, correction made to authors' informatio
An ADM 3+1 formulation for Smooth Lattice General Relativity
A new hybrid scheme for numerical relativity will be presented. The scheme
will employ a 3-dimensional spacelike lattice to record the 3-metric while
using the standard 3+1 ADM equations to evolve the lattice. Each time step will
involve three basic steps. First, the coordinate quantities such as the Riemann
and extrinsic curvatures are extracted from the lattice. Second, the 3+1 ADM
equations are used to evolve the coordinate data, and finally, the coordinate
data is used to update the scalar data on the lattice (such as the leg
lengths). The scheme will be presented only for the case of vacuum spacetime
though there is no reason why it could not be extended to non-vacuum
spacetimes. The scheme allows any choice for the lapse function and shift
vectors. An example for the Kasner cosmology will be presented and it
will be shown that the method has, for this simple example, zero discretisation
error.Comment: 18 pages, plain TeX, 5 epsf figues, gzipped ps file also available at
http://newton.maths.monash.edu.au:8000/preprints/3+1-slgr.ps.g
1 Finite-State Automata: Characterization Finite-State Acceptors
Definition (Non-deterministic finite-state acceptor (NFA)) A non-deterministic finite-state acceptor A is a 5-tuple (Q, Σ, q0, F, δ) where Q is a finite set of states Σ is the alphabet q0 ∈ Q is the start state F ⊆ Q is a set of final states δ: Q × Σ ∪ {ɛ} → 2 Q, the transition function Nondeterminism refers to the fact that a NFA has the power to be in several states at once. A transition may be labeled with ɛ. Nina Seemann (IMS) Formal Models in NLP: Finite-State Automata May 15, 2012 5Finite-State Acceptor
On Heavy-Quark Free Energies, Entropies, Polyakov Loop, and AdS/QCD
In this paper we explore some of the features of a heavy quark-antiquark pair
at finite temperature using a five-dimensional framework nowadays known as
AdS/QCD. We shall show that the resulting behavior is consistent with our
qualitative expectations of thermal gauge theory. Some of the results are in
good agreement with the lattice data that provides additional evidence for the
validity of the proposed model.Comment: 15 pages, 10 figures; v2: comments added, misprints correcte
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Modelling and simulation of flame cutting for steel plates with solid phases and melting
The goal of this work is to describe in detail a quasi-stationary state model which can be used to deeply understand the distribution of the heat in a steel plate and the changes in the solid phases of the steel and into liquid phase during the flame cutting process. We use a 3D-model similar to previous works from Thiebaud [1] and expand it to consider phases changes, in particular, austenite formation and melting of material. Experimental data is used to validate the model and study its capabilities. Parameters defining the shape of the volumetric heat source and the power density are calibrated to achieve good agreement with temperature measurements. Similarities and differences with other models from literature are discussed
Bures and Statistical Distance for Squeezed Thermal States
We compute the Bures distance between two thermal squeezed states and deduce
the Statistical Distance metric. By computing the curvature of this metric we
can identify regions of parameter space most sensitive to changes in these
parameters and thus lead to optimum detection statistics.Comment: 15 pages, 1 figure (not included - obtain from Author) To appear in
Journal of Physics
The critical exponents of the two-dimensional Ising spin glass revisited: Exact Ground State Calculations and Monte Carlo Simulations
The critical exponents for of the two-dimensional Ising spin glass
model with Gaussian couplings are determined with the help of exact ground
states for system sizes up to and by a Monte Carlo study of a
pseudo-ferromagnetic order parameter. We obtain: for the stiffness exponent
, for the magnetic exponent
and for the chaos exponent . From Monte Carlo simulations we
get the thermal exponent . The scaling prediction is
fulfilled within the error bars, whereas there is a disagreement with the
relation .Comment: 8 pages RevTeX, 7 eps-figures include
Algebraic topological analysis of time-sequence of digital images
This paper introduces an algebraic framework for a topological analysis of time-varying 2D digital binary–valued images, each of them defined as 2D arrays of pixels. Our answer is based on an algebraic-topological coding, called AT–model, for a nD (n=2,3) digital binary-valued image I consisting simply in taking I together with an algebraic object depending on it. Considering AT–models for all the 2D digital images in a time sequence, it is possible to get an AT–model for the 3D digital image consisting in concatenating the successive 2D digital images in the sequence. If the frames are represented in a quadtree format, a similar positive result can be derived
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