8,501 research outputs found
Overgeneration in the Higher Infinite
The Overgeneration Argument is a prominent objection against the model-theoretic account of logical consequence for second-order languages. In previous work we have offered a reconstruction of this argument which locates its source in the conflict between the neutrality of second-order logic and its alleged entanglement with mathematics. Some cases of this conflict concern small large cardinals. In this article, we show that in these cases the conflict can be resolved by moving from a set-theoretic implementation of the model-theoretic account to one which uses higher-order resources
Metalogic and the Overgeneration Argument
A prominent objection against the logicality of second-order logic is the so-called Overgeneration Argument. However, it is far from clear how this argument is to be understood. In the first part of the article, we examine the argument and locate its main source, namely, the alleged entanglement of second-order logic and mathematics. We then identify various reasons why the entanglement may be thought to be problematic. In the second part of the article, we take a metatheoretic perspective on the matter. We prove a number of results establishing that the entanglement is sensitive to the kind of semantics used for second-order logic. These results provide evidence that by moving from the standard set-theoretic semantics for second-order logic to a semantics which makes use of higher-order resources, the entanglement either disappears or may no longer be in conflict with the logicality of second-order logic
Weak Forces and Neutrino Oscillations under the standards of Hybrid Gravity with Torsion
We present a unifying approach where weak forces and neutrino oscillations
are interpreted under the same standards of torsional hybrid gravity. This
gravitational theory mixes metric and metric-affine formalism in presence of
torsion and allows to derive an effective scalar field which gives rise to a
running coupling for Dirac matter fields. In this picture, two phenomena
occurring at different energy scales can be encompassed under the dynamics of
such a single scalar field, which represents the further torsional and
curvature degrees of freedom.Comment: 13 page
Cosmological perfect-fluids in f(R) gravity
We show that an n-dimensional generalized Robertson-Walker (GRW) space-time
with divergence-free conformal curvature tensor exhibits a perfect fluid
stress-energy tensor for any f(R) gravity model. Furthermore we prove that a
conformally flat GRW space-time is still a perfect fluid in both f(R) and
quadratic gravity where other curvature invariants are considered.Comment: 13 pages, final versio
Soil quality evaluation under agro-silvo-pastoral Mediterranean management systems
According to Franzluebber (2002) the degree of stratification of soil organic C and N, as well as other parameters, with soil depth, expressed as a ratio, can indicate soil quality or soil ecosystem functioning and sustainability under different agricultural management. Stratification ratios > 2 indicate a higher soil quality and contribution to agriculture sustainability. A case study from northeastern Sardinia (Italy) is presented
High-Performance Passive Macromodeling Algorithms for Parallel Computing Platforms
This paper presents a comprehensive strategy for fast generation of passive macromodels of linear devices and interconnects on parallel computing hardware. Starting from a raw characterization of the structure in terms of frequency-domain tabulated scattering responses, we perform a rational curve fitting and a postprocessing passivity enforcement. Both algorithms are parallelized and cast in a form that is suitable for deployment on shared-memory multicore platforms. Particular emphasis is placed on the passivity characterization step, which is performed using two complementary strategies. The first uses an iterative restarted and deflated rational Arnoldi process to extract the imaginary Hamiltonian eigenvalues associated with the model. The second is based on an accuracy-controlled adaptive sampling. Various parallelization strategies are discussed for both schemes, with particular care on load balancing between different computing threads and memory occupation. The resulting parallel macromodeling flow is demonstrated on a number of medium- and large-scale structures, showing good scalability up to 16 computational core
Viscous corrections to anisotropic flow and transverse momentum spectra from transport theory
Viscous hydrodynamics is commonly used to model the evolution of the matter
created in an ultra-relativistic heavy-ion collision. It provides a good
description of transverse momentum spectra and anisotropic flow. These
observables, however, cannot be consistently derived using viscous
hydrodynamics alone, because they depend on the microscopic interactions at
freeze-out. We derive the ideal hydrodynamic limit and the first-order viscous
correction to anisotropic flow (, and ) and momentum spectrum
using a transport calculation. The linear response coefficient to the initial
anisotropy, , depends little on in the ideal
hydrodynamic limit. The viscous correction to the spectrum depends not only on
the differential cross section, but also on the initial momentum distribution.
This dependence is not captured by standard second-order viscous hydrodynamics.
The viscous correction to anisotropic flow increases with , but this
increase is slower than usually assumed in viscous hydrodynamic calculations.
In particular, it is too slow to explain the observed maximum of at
GeV/c.Comment: minor revisio
Patterns of trading profiles at the Nordic Stock Exchange. A correlation-based approach
We investigate the trading behavior of Finnish individual investors trading
the stocks selected to compute the OMXH25 index in 2003 by tracking the
individual daily investment decisions. We verify that the set of investors is a
highly heterogeneous system under many aspects. We introduce a correlation
based method that is able to detect a hierarchical structure of the trading
profiles of heterogeneous individual investors. We verify that the detected
hierarchical structure is highly overlapping with the cluster structure
obtained with the approach of statistically validated networks when an
appropriate threshold of the hierarchical trees is used. We also show that the
combination of the correlation based method and of the statistically validated
method provides a way to expand the information about the clusters of investors
with similar trading profiles in a robust and reliable way.Comment: 25 pages, 8 figure
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