pinecone/core-2020-05-10-deduplication huggingface dataset:
Complexity of Bradley-Manna-Sipma Lexicographic Ranking Functions

In this paper we turn the spotlight on a class of lexicographic ranking functions introduced by Bradley, Manna and Sipma in a seminal CAV 2005 paper, and establish for the first time the complexity of some problems involving the inference of such functions for linear-constraint loops (without precondition). We show that finding such a function, if one exists, can be done in polynomial time in a way which is sound and complete when the variables range over the rationals (or reals). We show that when variables range over the integers, the problem is harder—deciding the existence of a ranking function is coNP-complete. Next, we study the problem of minimizing the number of components in the ranking function (a.k.a. the dimension). This number is interesting in contexts like computing iteration bounds and loop parallelization. Surprisingly, and unlike the situation for some other classes of lexicographic ranking functions, we find that even deciding whether a two-component ranking function exists is harder than the unrestricted problem: NP-complete over the rationals and Σ P 2 - complete over the integers
On Deciding Local Theory Extensions via E-matching

Satisfiability Modulo Theories (SMT) solvers incorporate decision procedures
for theories of data types that commonly occur in software. This makes them
important tools for automating verification problems. A limitation frequently
encountered is that verification problems are often not fully expressible in
the theories supported natively by the solvers. Many solvers allow the
specification of application-specific theories as quantified axioms, but their
handling is incomplete outside of narrow special cases.
  In this work, we show how SMT solvers can be used to obtain complete decision
procedures for local theory extensions, an important class of theories that are
decidable using finite instantiation of axioms. We present an algorithm that
uses E-matching to generate instances incrementally during the search,
significantly reducing the number of generated instances compared to eager
instantiation strategies. We have used two SMT solvers to implement this
algorithm and conducted an extensive experimental evaluation on benchmarks
derived from verification conditions for heap-manipulating programs. We believe
that our results are of interest to both the users of SMT solvers as well as
their developers
Who is an immigrant and who requires integration? Categorizing in European policies

Contains fulltext :
                  170795.pdf (publisher's version ) (Open Access)Some immigrants are problematized, while others are not. As categories form the backbone of policies, they formally define (i) who is a wanted and who is an unwanted immigrant and (ii) who requires integration and who does not. Gender studies and migration and ethnic studies show how categories both construct and reproduce inequality. We argue that this critical perspective is beneficial to studies on European immigration and integration policies in order to show how inclusion and exclusion work when categories are used in the policy chain
Sending Country Policies

This chapter explores the twin central questions of how and why countries of origin reach out to expatriate populations. It first outlines basic concepts and typologies related to sending country policies, focusing particularly on key countries of origin of migrants settled within the European Union. Second, the chapter reviews central explanations for the emergence of sending country policies. However, sending countries do not reach out to their emigrants in equal measure. Differences are therefore examined in the outreach policies of sending countries and in sending countries’ transnational relations with diasporas. The last part of the chapter discusses the nexus between sending country policies and migrant integration in the country of residence. On the basis of existing research, the chapter argues that sending country policies may intersect with migrants' integration in a number of ways. For example, migrant sending countries may seek to strengthen the upward mobility of their expatriate citizens in their place of residence abroad, and they may call for greater protection of migrant workers in precarious labour situations. Little is currently known about how migrants and diasporas respond to these policies and how they are perceived by political actors of countries of residence. This is an area for further study. More analysis is also needed to determine the extent that sending country outreach policies aimed at bonding with and supporting citizens abroad challenge territorial policy sovereignty and the strength of receiving countries in agenda-setting in international cooperation on migration and migrant settlement
On Automation of CTL* Verification for Infinite-State Systems

In this paper we introduce the first known fully automated tool for symbolically proving CTL* properties of (infinite-state) integer programs. The method uses an internal encoding which facilitates reasoning about the subtle interplay between the nesting of path and state temporal operators that occurs within \ctlstar proofs. A precondition synthesis strategy is then used over a program transformation which trades nondeterminism in the transition relation for nondeterminism explicit in variables predicting future outcomes when necessary. We show the viability of our approach in practice using examples drawn from device drivers and various industrial examples.Peer-reviewedPost-printComputer Aided Verification, San Francisco, CA, US
Abstract Interpretation with Higher-Dimensional Ellipsoids and Conic
  Extrapolation

The inference and the verification of numerical relationships among variables
of a program is one of the main goals of static analysis. In this paper, we
propose an Abstract Interpretation framework based on higher-dimensional
ellipsoids to automatically discover symbolic quadratic invariants within
loops, using loop counters as implicit parameters. In order to obtain
non-trivial invariants, the diameter of the set of values taken by the
numerical variables of the program has to evolve (sub-)linearly during loop
iterations. These invariants are called ellipsoidal cones and can be seen as an
extension of constructs used in the static analysis of digital filters.
Semidefinite programming is used to both compute the numerical results of the
domain operations and provide proofs (witnesses) of their correctness.Comment: Proceedings, Part I, Computer Aided Verification 27th International
  Conference, CAV 2015, San Francisco, CA, USA, July 18-24, 201
Synthesising Executable Gene Regulatory Networks from Single-Cell Gene Expression Data

Recent experimental advances in biology allow researchers to obtain gene expression profiles at single-cell resolution over hundreds, or even thousands of cells at once. These single-cell measurements provide snapshots of the states of the cells that make up a tissue, instead of the population-level averages provided by conventional high-throughput experiments. This new data therefore provides an exciting opportunity for computational modelling. In this paper we introduce the idea of viewing single-cell gene expression profiles as states of an asynchronous Boolean network, and frame model inference as the problem of reconstructing a Boolean network from its state space. We then give a scalable algorithm to solve this synthesis problem. We apply our technique to both simulated and real data. We first apply our technique to data simulated from a well established model of common myeloid progenitor differentiation. We show that our technique is able to recover the original Boolean network rules. We then apply our technique to a large dataset taken dur- ing embryonic development containing thousands of cell measurements. Our technique synthesises matching Boolean networks, and analysis of these models yields new predictions about blood development which our experimental collaborators were able to verify.Peer-reviewedPost-printComputer Aided Verification, San Francisco, CA, US
Earthquake and people : the Maltese experience of the 1908 Messina earthquake

On December 28, 1908 at 5:20 a.m. local time, a devastating earthquake (Mw = 7.2) struck Southern Italy along the Messina Strait (Fig. 1). This event caused severe ground shaking throughout the region and triggered a local tsunami. As result the cities of Messina along Sicily’s coast and Reggio di Calabria were completely destroyed (Baratta, 1910) causing more than 120,000 fatalities and with many left without shelter. The effects of the earthquake were felt within a 300-kilometer radius. Rescuers searched through the rubble for weeks, and people were still being pulled out alive days later, but thousands remained buried there. The 1908 earthquake had a significant impact on buildings and people and local communities which were displaced. The Maltese experience of the Messina 1908 earthquake relied on communication which reached Malta after the event. The assessment of the Maltese experience of the Messina Earthquake has so far been carried out with reference to published newspaper reports and other brief accounts including Herbert Ganado’s Rajt Malta Tinbidel. Alfons Maria Galea a Maltese author and filanthropist published a book in Maltese on the earthquake and its devastating effects in the popular educational series il-Kotba tal-Mogħdija taż-Żmien just a few weeks after the event. The book is a vivid account of the destruction caused by the earthquake, the suffering of the survivors and the reaction of the population in reviving the city. The document presents first-hand accounts of the events in sufficient detail to give a clear picture of the severity of the event, extents of the damage and impact on the population. It is mostly based on accounts received by Galea from persons in institutions including religious orders in Sicily who he knew. Newspaper reports in Malta and other countries together with Galea’s book present clear first-hand accounts of this event and provide information on the building deficiencies and damage, limitations of communication infrastructure during that period, limits to timely emergency response to support the population and emergency action at the beginning of the 20th century.peer-reviewe
The Easter Sunday 2011 earthquake swarm offshore Malta : analysis on felt reports

In the last forty years, Malta has only experienced a few occasional tremors from local or regional earthquakes, with only some being reported briefly in the local newspapers. These reports gave limited qualitative and quantitative information about the shaking experience felt across the islands. The Seismic Monitoring and Research Unit at the University of Malta has put in place a ‘Did you feel an earthquake?’ online questionnaire in order to start gathering information from locally felt earthquake related shaking. On Easter Sunday 24th of April 2011 windows rattled, doors shook open, and furniture shifted in many homes across Malta when a series of earthquakes occurred 38 km off the eastern coast. In total, the SMRU located 15 earthquakes with magnitudes ranging from M L 1.8 to 4.1 over a period of 4 days. A total of 489 felt reports were submitted through the online questionnaire. The compilation of the data is a first of its kind for the Maltese islands. Here we present a summary of the reports following the main shock. A maximum intensity value IV on the European Macroseismic Scale was assigned. No structural damage was reported. The data reflects the demographics as well as the different types of buildings found across the archipelago.peer-reviewe
Cache-Oblivious Iterated Predecessor Queries via Range Coalescing

In this paper we develop an optimal cache-oblivious data structure that solves the iterated predecessor problem. Given k static sorted lists  L[subscript 1],L[subscript 2],…,L[subscript k] of average length n and a query value q, the iterated predecessor problem is to find the largest element in each list which is less than q. Our solution to this problem, called “range coalescing”, requires  O(log[subscript B+1]n+k/B) memory transfers for a query on a cache of block size B, which is information-theoretically optimal. The range-coalescing data structure consumes O(kn) space, and preprocessing requires only O(kn / B) memory transfers with high probability, given a tall cache of size  M=Ω(B[superscript 2])
Neutrino-driven Explosions

The question why and how core-collapse supernovae (SNe) explode is one of the
central and most long-standing riddles of stellar astrophysics. A solution is
crucial for deciphering the SN phenomenon, for predicting observable signals
such as light curves and spectra, nucleosynthesis, neutrinos, and gravitational
waves, for defining the role of SNe in the evolution of galaxies, and for
explaining the birth conditions and properties of neutron stars (NSs) and
stellar-mass black holes. Since the formation of such compact remnants releases
over hundred times more energy in neutrinos than the SN in the explosion,
neutrinos can be the decisive agents for powering the SN outburst. According to
the standard paradigm of the neutrino-driven mechanism, the energy transfer by
the intense neutrino flux to the medium behind the stagnating core-bounce
shock, assisted by violent hydrodynamic mass motions (sometimes subsumed by the
term "turbulence"), revives the outward shock motion and thus initiates the SN
blast. Because of the weak coupling of neutrinos in the region of this energy
deposition, detailed, multidimensional hydrodynamic models including neutrino
transport and a wide variety of physics are needed to assess the viability of
the mechanism. Owing to advanced numerical codes and increasing supercomputer
power, considerable progress has been achieved in our understanding of the
physical processes that have to act in concert for the success of
neutrino-driven explosions. First studies begin to reveal observational
implications and avenues to test the theoretical picture by data from
individual SNe and SN remnants but also from population-integrated observables.
While models will be further refined, a real breakthrough is expected through
the next Galactic core-collapse SN, when neutrinos and gravitational waves can
be used to probe the conditions deep inside the dying star. (abridged)Comment: Author version of chapter for 'Handbook of Supernovae,' edited by A.
  Alsabti and P. Murdin, Springer. 54 pages, 13 figure
High Energy Cosmic Rays From Supernovae

Cosmic rays are charged relativistic particles that reach the Earth with
extremely high energies, providing striking evidence of the existence of
effective accelerators in the Universe. Below an energy around $\sim 10^{17}$
eV cosmic rays are believed to be produced in the Milky Way while above that
energy their origin is probably extragalactic. In the early '30s supernovae
were already identified as possible sources for the Galactic component of
cosmic rays. After the '70s this idea has gained more and more credibility
thanks to the the development of the diffusive shock acceleration theory, which
provides a robust theoretical framework for particle energization in
astrophysical environments. Afterwards, mostly in recent years, much
observational evidence has been gathered in support of this framework,
converting a speculative idea in a real paradigm. In this Chapter the basic
pillars of this paradigm will be illustrated. This includes the acceleration
mechanism, the non linear effects produced by accelerated particles onto the
shock dynamics needed to reach the highest energies, the escape process from
the sources and the transportation of cosmic rays through the Galaxy. The
theoretical picture will be corroborated by discussing several observations
which support the idea that supernova remnants are effective cosmic ray
factories.Comment: Final draft of a chapter in "Handbook of Supernovae" edited by Athem
  W. Alsabti and Paul Murdi
The effects of supernovae on the dynamical evolution of binary stars and
  star clusters

In this chapter I review the effects of supernovae explosions on the
dynamical evolution of (1) binary stars and (2) star clusters.
  (1) Supernovae in binaries can drastically alter the orbit of the system,
sometimes disrupting it entirely, and are thought to be partially responsible
for `runaway' massive stars - stars in the Galaxy with large peculiar
velocities. The ejection of the lower-mass secondary component of a binary
occurs often in the event of the more massive primary star exploding as a
supernova. The orbital properties of binaries that contain massive stars mean
that the observed velocities of runaway stars (10s - 100s km s$^{-1}$) are
consistent with this scenario.
  (2) Star formation is an inherently inefficient process, and much of the
potential in young star clusters remains in the form of gas. Supernovae can in
principle expel this gas, which would drastically alter the dynamics of the
cluster by unbinding the stars from the potential. However, recent numerical
simulations, and observational evidence that gas-free clusters are observed to
be bound, suggest that the effects of supernova explosions on the dynamics of
star clusters are likely to be minimal.Comment: 16 pages, to appear in the 'Handbook of Supernovae', eds. Paul Murdin
  and Athem Alsabti. This version replaces an earlier version that contained
  several typo
Supernovae from massive stars

Massive stars, by which we mean those stars exploding as core collapse
supernovae, play a pivotal role in the evolution of the Universe. Therefore,
the understanding of their evolution and explosion is fundamental in many
branches of physics and astrophysics, among which, galaxy evolution,
nucleosynthesis, supernovae, neutron stars and pulsars, black holes, neutrinos
and gravitational waves. In this chapter, the author presents an overview of
the presupernova evolution of stars in the range between 13 and 120 $\rm
M_\odot$, with initial metallicities between [Fe/H]=-3 and [Fe/H]=0 and initial
rotation velocities $\rm v=0,~150,~300~km/s$. Emphasis is placed upon those
evolutionary properties that determine the final fate of the star with special
attention to the interplay among mass loss, mixing and rotation. A general
picture of the evolution and outcome of a generation of massive stars, as a
function of the initial mass, metallicity and rotation velocity, is finally
outlined.Comment: Author version of a chapter for 'Handbook of Supernovae,' edited by
  A. Alsabti and P. Murdin, Springer. 59 pages, 27 figure
Supernovae from rotating stars

The present paper discusses the main physical effects produced by stellar
rotation on presupernovae, as well as observations which confirm these effects
and their consequences for presupernova models. Rotation critically influences
the mass of the exploding cores, the mass and chemical composition of the
envelopes and the types of supernovae, as well as the properties of the
remnants and the chemical yields. In the formation of gamma-ray bursts,
rotation and the properties of rotating stars appear as the key factor. In
binaries, the interaction between axial rotation and tidal effects often leads
to interesting and unexpected results. Rotation plays a key role in shaping the
evolution and nucleosynthesis in massive stars with very low metallicities
(metallicity below about the Small Magellanic Cloud metallicity down to
Population III stars). At solar and higher metallicities, the effects of
rotation compete with those of stellar winds. In close binaries, the
synchronisation process can lock the star at a high rotation rate despite
strong mass loss and thus both effects, rotation and stellar winds, have a
strong impact. In conclusion, rotation is a key physical ingredient of the
stellar models and of presupernova stages, and the evolution both of single
stars and close binaries. Moreover, important effects are expected along the
whole cosmic history.Comment: 36 pages, 15 figures, published in Handbook of Supernovae, A.W.
  Alsabti and P. Murdin (eds), Springe
Gould's Belt: Local Large Scale Structure in the Milky Way

Gould's Belt is a flat local system composed of young OB stars, molecular
clouds and neutral hydrogen within 500 pc from the Sun. It is inclined about 20
degrees to the galactic plane and its velocity field significantly deviates
from rotation around the distant center of the Milky Way. We discuss possible
models of its origin: free expansion from a point or from a ring, expansion of
a shell, or a collision of a high velocity cloud with the plane of the Milky
Way. Currently, no convincing model exists. Similar structures are identified
in HI and CO distribution in our and other nearby galaxies.Comment: 9 pages, 3 figures, Handbook of Supernova
Spectra of supernovae in the nebular phase

When supernovae enter the nebular phase after a few months, they reveal
spectral fingerprints of their deep interiors, glowing by radioactivity
produced in the explosion. We are given a unique opportunity to see what an
exploded star looks like inside. The line profiles and luminosities encode
information about physical conditions, explosive and hydrostatic
nucleosynthesis, and ejecta morphology, which link to the progenitor properties
and the explosion mechanism. Here, the fundamental properties of spectral
formation of supernovae in the nebular phase are reviewed. The formalism
between ejecta morphology and line profile shapes is derived, including effects
of scattering and absorption. Line luminosity expressions are derived in
various physical limits, with examples of applications from the literature. The
physical processes at work in the supernova ejecta, including gamma-ray
deposition, non-thermal electron degradation, ionization and excitation, and
radiative transfer are described and linked to the computation and application
of advanced spectral models. Some of the results derived so far from
nebular-phase supernova analysis are discussed.Comment: Book chapter for 'Handbook of Supernovae,' edited by Alsabti and
  Murdin, Springer. 51 pages, 14 figure
Shock breakout theory

The earliest supernova (SN) emission is produced when the optical depth of
the plasma lying ahead of the shock, which ejects the envelope, drops below
c/v, where v is the shock velocity. This "breakout" may occur when the shock
reaches the edge of the star, producing a bright X-ray/UV flash on time scales
of seconds to a fraction of an hour, followed by UV/optical "cooling" emission
from the expanding cooling envelope on a day time-scale. If the optical depth
of circumstellar material (CSM) ejected from the progenitor star prior to the
explosion is larger than c/v, the breakout will take place at larger radii,
within the CSM, extending its duration to days time scale. The properties of
the early, breakout and cooling, emission carry unique signatures of the
structure of the progenitor star (e.g. its radius and surface composition) and
of its mass-loss history. The recent progress of wide-field transient surveys
enable SN detections on a day time scale, and are being used to set unique
constraints on the progenitors of SNe of all types. This chapter includes a
pedagogical description of SN breakout theory, and a concise overview of what
we have learned from observations so far, and of advances in observational
capabilities that are required in order to make further significant progress.Comment: review chapter, to appear in Handbook of Supernovae, edited by Athem
  W. Alsabti and Paul Murdin (Springer