pinecone/core-2020-05-10-deduplication huggingface dataset:
Topological Structure of the QCD Vacuum Revealed by Overlap Fermions

Overlap fermions preserve a remnant of chiral symmetry on the lattice. They
are a powerful tool to investigate the topological structure of the vacuum of
Yang-Mills theory and full QCD. Recent results concerning the localization of
topological charge and the localization and local chirality of the overlap
eigenmodes are reported. The charge distribution is radically different, if a
spectral cut-off for the Dirac eigenmodes is applied. The density q(x) is
changing from the scale-a charge density (with full lattice resolution) to the
ultraviolet filtered charge density. The scale-a density, computed on the Linux
cluster of LRZ, has a singular, sign-coherent global structure of co-dimension
1 first described by the Kentucky group. We stress, however, the cluster
properties of the UV filtered topological density resembling the instanton
picture. The spectral cut-off can be mapped to a bosonic smearing procedure.
The UV filtered field strength reveals a high degree of (anti)selfduality at
"hot spots" of the action. The fermionic eigenmodes show a high degree of local
chirality. The lowest modes are seen to be localized in low-dimensional
space-time regions.Comment: 13 pages, 11 figures, accepted to appear in the Proceedings of "HLRB,
  KONWIHR and Linux-Cluster: Review, Results and Future Projects Workshop",
  Leibniz Rechenzentrum Munich, December 200
Material-Specific Investigations of Correlated Electron Systems

We present the results of numerical studies for selected materials with
strongly correlated electrons using a combination of the local-density
approximation and dynamical mean-field theory (DMFT). For the solution of the
DMFT equations a continuous-time quantum Monte-Carlo algorithm was employed.
All simulations were performed on the supercomputer HLRB II at the Leibniz
Rechenzentrum in Munich. Specifically we have analyzed the pressure induced
metal-insulator transitions in Fe2O3 and NiS2, the charge susceptibility of the
fluctuating-valence elemental metal Yb, and the spectral properties of a
covalent band-insulator model which includes local electronic correlations.Comment: 14 pages, 7 figures, to appear in "High Performance Computing in
  Science and Engineering, Garching 2009" (Springer
Alpha-cluster Condensations in Nuclei and Experimental Approaches for
  their Studies

The formation of alpha-clusters in nuclei close to the decay thresholds is
discussed. These states can be considered to be boson-condensates, which are
formed in a second order phase transition in a mixture of nucleons and
alpha-particles. The de Broglie wavelength of the alpha-particles is larger
than the nuclear diameter, therefore the coherent properties of the
alpha-particles give particular effects for the study of such states. The
states are above the thresholds thus the enhanced emission of multiple-alphas
into the same direction is observed. The probability for the emission of
multiple-alphas is not described by Hauser-Feshbach theory for compound nucleus
decay.Comment: 21 pages, 12 figures
Di-neutron clustering and deuteron-like tensor correlation in nuclear
  structure focusing on 11Li

11Li is a Borromean nucleus, where two out of three objects as 9Li + n and
two neutrons independently do not form bound systems. Two neutrons should form
a di-neutron cluster in the nuclear field generated by the 9Li core nucleus. We
treat di-neutron clustering by solving the two neutron relative wave function
precisely by using the bare nucleon-nucleon interaction so that the spatial
clustering structure is obtained quantitatively within the whole 11Li nucleus.
This di-neutron clustering is an essential dynamics to form the halo structure
by making a compact di-neutron cluster, which distributes loosely around the
9Li core. The di-neutron clustering is a new concept and is a general
phenomenon in neutron skin and neutron halo nuclei. This quantitative
description of di-neutron clustering has made it necessary to consider another
important deuteron-like tensor correlation, which is caused by strong tensor
interaction in the nucleon-nucleon interaction. The tensor interaction
originates from pion exchange and known to provide large attraction to form the
4He nucleus. The unique feature of the tensor correlation is to make highly
correlated deuteron-like excitation, which interferes with shell model like
structure in a unique way. This dynamical effect removes the magic number
effect and makes easy the participation of the s-wave neutrons. Hence, there
are pairing and deuteron-like tensor correlations in addition to the mean field
structure in 9Li. The combined system of two additional neutrons with the
correlated 9Li provides the halo phenomenon, in which the di-neutron clustering
develops with the help of large s-wave component caused by the deuteron-like
tensor correlation. In this lecture note, we would like to introduce these two
new concepts in a systematic manner and fill a gap between the halo phenomenon
and the microscopic reason for this interesting phenomenon.Comment: 58 pages, to be published in Lecture Note in Physics Vol. 818
  (Springer), "Clusters in Nuclei" Volume 1, corrected figure
Endogenous credit dynamics as source of business cycles in the EURACE model

The paper investigates the relationship between the amount of credit money in the economy and the variability of output and prices in the EURACE model. First we examine if the decision about dividends payment by the firms can affect this variability, then we adopt the policy measure of quantitative easing, that has been largely used by the Fed and the Bank of England during the recent crisis, in order to understand its effect on economic instability. Results show the emer- gence of endogenous business cycles which are mainly due to the interplay between the real economic activity and its financing through the credit market. In particular, the amplitude of the business cycles strongly raises when the fraction of earnings paid out by firms as dividends is higher, that is when firms are more constrained to borrow credit money to fund their activity
Evolutionary estimation of a Coupled Markov Chain credit risk model

There exists a range of different models for estimating and simulating credit
risk transitions to optimally manage credit risk portfolios and products. In
this chapter we present a Coupled Markov Chain approach to model rating
transitions and thereby default probabilities of companies. As the likelihood
of the model turns out to be a non-convex function of the parameters to be
estimated, we apply heuristics to find the ML estimators. To this extent, we
outline the model and its likelihood function, and present both a Particle
Swarm Optimization algorithm, as well as an Evolutionary Optimization algorithm
to maximize the likelihood function. Numerical results are shown which suggest
a further application of evolutionary optimization techniques for credit risk
management
On the Complexity of Local Search for Weighted Standard Set Problems

In this paper, we study the complexity of computing locally optimal solutions
for weighted versions of standard set problems such as SetCover, SetPacking,
and many more. For our investigation, we use the framework of PLS, as defined
in Johnson et al., [JPY88]. We show that for most of these problems, computing
a locally optimal solution is already PLS-complete for a simple neighborhood of
size one. For the local search versions of weighted SetPacking and SetCover, we
derive tight bounds for a simple neighborhood of size two. To the best of our
knowledge, these are one of the very few PLS results about local search for
weighted standard set problems
Finding subsets of positive measure

An important theorem of geometric measure theory (first proved by Besicovitch
and Davies for Euclidean space) says that every analytic set of non-zero
$s$-dimensional Hausdorff measure $\mathcal H^s$ contains a closed subset of
non-zero (and indeed finite) $\mathcal H^s$-measure. We investigate the
question how hard it is to find such a set, in terms of the index set
complexity, and in terms of the complexity of the parameter needed to define
such a closed set. Among other results, we show that given a (lightface)
$\Sigma^1_1$ set of reals in Cantor space, there is always a
$\Pi^0_1(\mathcal{O})$ subset on non-zero $\mathcal H^s$-measure definable from
Kleene's $\mathcal O$. On the other hand, there are $\Pi^0_2$ sets of reals
where no hyperarithmetic real can define a closed subset of non-zero measure.Comment: This is an extended journal version of the conference paper "The
  Strength of the Besicovitch--Davies Theorem". The final publication of that
  paper is available at Springer via
  http://dx.doi.org/10.1007/978-3-642-13962-8_2
On the completeness of quantum computation models

The notion of computability is stable (i.e. independent of the choice of an
indexing) over infinite-dimensional vector spaces provided they have a finite
"tensorial dimension". Such vector spaces with a finite tensorial dimension
permit to define an absolute notion of completeness for quantum computation
models and give a precise meaning to the Church-Turing thesis in the framework
of quantum theory. (Extra keywords: quantum programming languages, denotational
semantics, universality.)Comment: 15 pages, LaTe
Approximate Self-Assembly of the Sierpinski Triangle

The Tile Assembly Model is a Turing universal model that Winfree introduced
in order to study the nanoscale self-assembly of complex (typically aperiodic)
DNA crystals. Winfree exhibited a self-assembly that tiles the first quadrant
of the Cartesian plane with specially labeled tiles appearing at exactly the
positions of points in the Sierpinski triangle. More recently, Lathrop, Lutz,
and Summers proved that the Sierpinski triangle cannot self-assemble in the
"strict" sense in which tiles are not allowed to appear at positions outside
the target structure. Here we investigate the strict self-assembly of sets that
approximate the Sierpinski triangle. We show that every set that does strictly
self-assemble disagrees with the Sierpinski triangle on a set with fractal
dimension at least that of the Sierpinski triangle (roughly 1.585), and that no
subset of the Sierpinski triangle with fractal dimension greater than 1
strictly self-assembles. We show that our bounds are tight, even when
restricted to supersets of the Sierpinski triangle, by presenting a strict
self-assembly that adds communication fibers to the fractal structure without
disturbing it. To verify this strict self-assembly we develop a generalization
of the local determinism method of Soloveichik and Winfree
Focusing in Asynchronous Games

Game semantics provides an interactive point of view on proofs, which enables
one to describe precisely their dynamical behavior during cut elimination, by
considering formulas as games on which proofs induce strategies. We are
specifically interested here in relating two such semantics of linear logic, of
very different flavor, which both take in account concurrent features of the
proofs: asynchronous games and concurrent games. Interestingly, we show that
associating a concurrent strategy to an asynchronous strategy can be seen as a
semantical counterpart of the focusing property of linear logic
How powerful are integer-valued martingales?

In the theory of algorithmic randomness, one of the central notions is that
of computable randomness. An infinite binary sequence X is computably random if
no recursive martingale (strategy) can win an infinite amount of money by
betting on the values of the bits of X. In the classical model, the martingales
considered are real-valued, that is, the bets made by the martingale can be
arbitrary real numbers. In this paper, we investigate a more restricted model,
where only integer-valued martingales are considered, and we study the class of
random sequences induced by this model.Comment: Long version of the CiE 2010 paper
Evaluating MDC with incentives in P2PTV systems

The popularity of P2P video streaming is raising the interest of broadcasters, operators and service providers. Concretely, mesh-pull based P2P systems are the most extended ones. Despite these systems address scalability efficiently, they still present limitations that difficult them to offer the same user experience in comparison with traditional TV. These ones are mainly the freeriding effect, long start-up delays and the impact of churn and bandwidth heterogeneity.\ud
In this paper we study the performance of Multiple Description Coding (MDC) combined with the use of incentives for redistribution in order to mitigate some of them by means of simulations. Simulation results show that the use of MDC and incentive-based scheduling strategies improve the overall performance of the system. Moreover, an extended version of the P2PTVSim simulator has been developed to support MDC and incentives.Peer ReviewedPostprint (published version
Scalable service performance monitoring

Dependable performance measurement is a common requirement for all on-line services. The ongoing tendency to outsource not only infrastructure, but also software parts to several suppliers, creates a new challenge to providers. Traditional solutions cannot easily monitor service performance as perceived by end users, since providers do not have control over all hardware/software involved. Our research focuses on evaluating how data passively collected from network devices can be used to verify end-to-end service performance. Our goal is to compare this approach with current methods used to monitor distributed services. Given the constant mutation of applications on the Internet, as well as the fast increase of the number of users, we are looking for flexible and scalable solutions
Autonomous resource-aware scheduling of large-scale media workflows

The media processing and distribution industry generally requires considerable resources to be able to execute the various tasks and workflows that constitute their business processes. The latter processes are often tied to critical constraints such as strict deadlines. A key issue herein is how to efficiently use the available computational, storage and network resources to be able to cope with the high work load. Optimizing resource usage is not only vital to scalability, but also to the level of QoS (e.g. responsiveness or prioritization) that can be provided. We designed an autonomous platform for scheduling and workflow-to-resource assignment, taking into account the different requirements and constraints. This paper presents the workflow scheduling algorithms, which consider the state and characteristics of the resources (computational, network and storage). The performance of these algorithms is presented in detail in the context of a European media processing and distribution use-case
A Suite of semantic Web tools supporting development of multilingual ontologies

The multilingual aspects which characterize the (Semantic) Web and the constant demand for more understandable and easy-to-share forms of knowledge representation, push for a more "linguistically aware" approach to ontology development and foresees an environment where formal semantics could coexist with natural language, contributing to improve "shareability" of the content they describe. As a consequence ontologies should be enriched to both cover formally expressed conceptual knowledge as well as to expose content in a linguistically motivated fashion. In this paper we present a suite of tools, libraries and ontolo-gies, ranging from ontology development to language resources access and man-agement, supporting the development of multilingual ontologies. The contribution of this work, going beyond mere tool presentation, is two-fold: the presented tools implicitly embody a new way (methodology?) of rethinking the development of ontologies in terms of making their content easy reusable and comprehensible; moreover, they represent living proofs of software engineering principles asso-ciated to software reuse, documentation, modularity, interaction analysis, applied to the domain of Knowledge Management Software. © 2010 Springer-Verlag Berlin Heidelberg
Tile-packing tomography is NP-hard

Discrete tomography deals with reconstructing finite spatial objects from their projections. The objects we study in this paper are called tilings or tile-packings, and they consist of a number of disjoint copies of a fixed tile, where a tile is defined as a connected set of grid\ud
points. A row projection specifies how many grid points are covered by tiles in a given row; column projections are defined analogously. For a fixed tile, is it possible to reconstruct its tilings from their projections in polynomial time? It is known that the answer to this question is affirmative if the tile is a bar (its width or height is 1), while for some other types of tiles NP-hardness results have been shown in the literature. In this paper we present a complete solution to this question by showing that the problem remains NP-hard for all tiles other than bars.Peer ReviewedPostprint (published version
The Rectilinear κ-Bends TSP

We study a hard geometric problem. Given n points in the plane and a positive integer k, the Rectilinear  k  -Bends Traveling Salesman Problem asks if there is a piecewise linear tour through the n points with at most k bends where every line-segment in the path is either horizontal or vertical. The problem has applications in VLSI design. We prove that this problem belongs to the class FPT (fixed-parameter tractable). We give an algorithm that runs in O(kn  2?+?k  4k   n) time by kernelization. We present two variations on the main result. These variations are derived from the distinction between line-segments and lines. Note that a rectilinear tour with k bends is a cover with k line-segments, and therefore a cover by lines. We derive FPT-algorithms using bounded-search-tree techniques and improve the time complexity for these variants.Griffith Sciences, School of Information and Communication TechnologyFull Tex
On elementary equivalence in fuzzy predicate logics

Our work is a contribution to the model theory of fuzzy predicate logics. In this paper we characterize elementary equivalence between models of fuzzy predicate logic using elementary mappings. Refining the method of diagrams we give a solution to an open problem of Hájek and Cintula (J Symb Log 71(3):863–880, 2006, Conjectures 1 and 2). We investigate also the properties of elementary extensions in witnessed and quasi-witnessed theories, generalizing some results of Section 7 of Hájek and Cintula (J Symb Log 71(3):863–880, 2006) and of Section 4 of Cerami and Esteva (Arch Math Log 50(5/6):625–641, 2011) to non-exhaustive model
Formal Proof of a Wave Equation Resolution Scheme: the Method Error

Popular finite difference numerical schemes for the resolution of the
one-dimensional acoustic wave equation are well-known to be convergent. We
present a comprehensive formalization of the simplest one and formally prove
its convergence in Coq. The main difficulties lie in the proper definition of
asymptotic behaviors and the implicit way they are handled in the mathematical
pen-and-paper proofs. To our knowledge, this is the first time such kind of
mathematical proof is machine-checked.Comment: replaces arXiv:1001.489
Deciding Kleene Algebras in Coq

International audienceWe present a reflexive tactic for deciding the equational theory of Kleene algebras in the Coq proof assistant. This tactic relies on a careful implementation of efficient finite automata algorithms, so that it solves casual equations instantaneously and properly scales to larger expressions. The decision procedure is proved correct and complete: correctness is established w.r.t. any model by formalising Kozen's initiality theorem; a counter-example is returned when the given equation does not hold. The correctness proof is challenging: it involves both a precise analysis of the underlying automata algorithms and a lot of algebraic reasoning. In particular, we have to formalise the theory of matrices over a Kleene algebra. We build on the recent addition of firstorder typeclasses in Coq in order to work efficiently with the involved algebraic structures
Case-Analysis for Rippling and Inductive Proof

Rippling is a heuristic used to guide rewriting and is typically used for inductive theorem proving. We introduce a method to support case-analysis within rippling. Like earlier work, this allows goals containing if-statements to be proved automatically. The new contribution is that our method also supports case-analysis on datatypes. By locating the case-analysis as a step within rippling we also maintain the termination. The work has been implemented in IsaPlanner and used to extend the existing inductive proof method. We evaluate this extended prover on a large set of examples from Isabelle’s theory library and from the inductive theorem proving literature. We find that this leads to a significant improvement in the coverage of inductive theorem proving. The main limitations of the extended prover are identified, highlight the need for advances in the treatment of assumptions during rippling and when conjecturing lemmas
Rectification of Preferences in a Fuzzy Environment.

In this paper we consider a complete fuzzy preference structure, defined by means of a constructive approach associated to the necessary learning process in a decision making problem. Preference relations are successively\ud
assigned over a given set of alternatives with the possibility of revision and rectification, subject to a certain set of beliefs which sustain the construction of\ud
different viewpoints. Measures of information are then considered in this process for a formal identification of uncertainty due to ignorance, a concept that is closely related to ambiguity as defined by Fishburn (1993). Finally, a coherence criterion is proposed in order to study the importance of preferences, in such a way that an indirect and comparative analysis between them is needed so\ud
outcomes may be coherently organized
Fuzzy regions: adding subregions and the impact on surface and distance calculation

In the concept of fuzzy regions we introduced before, a region was considered to be a fuzzy set of points, each having its own membership grade. While this allows the modelling of regions in which points only partly belong to the region, it has the downside that all the points are considered independently, which is too loose a restriction for some situations. The model is not able to support the fact that some points may be linked together. In this contribution, we propose an extension to the model, so that points can be made related to one another. It will permit the user to, for instance, specify points or even (sub)regions within the fuzzy region that are linked together: they all belong to the region to the same extent at the same time. By letting the user specify such subregions, the accuracy Of the model can be increased: the model can match the real situation better; while at the same time decreasing the fuzziness: if points are known to be related, there is no need to consider them independently. As an example, the use of such a fuzzy region to represent a lake with a variable water level can be considered: as the water level rises, a set of points will become flooded; it is interesting to represent this set of points as a. subset of the region, as these points are somewhat related (the same can be done for different water levels). The impact of this extension to the model on both surface area calculation an distance measurement are considered, and new appropriate definitions are introduced