174 research outputs found
Zero Jordan product determined Banach algebras
A Banach algebra is said to be a zero Jordan product determined Banach
algebra if every continuous bilinear map , where
is an arbitrary Banach space, which satisfies whenever
, are such that , is of the form
for some continuous linear map . We show
that all -algebras and all group algebras of amenable locally
compact groups have this property, and also discuss some applications
Loss of largest and oldest individuals of the Montpellier snake correlates with recent warming in the southeastern Iberian Peninsula
The effects of climate change on organisms are now being extensively studied in many different taxa. However, the variation in body size, usually shrinkage in response to increasing temperature, has received little attention regarding to reptiles. During past periods of global warming, many organisms shrank in size, and current evidence and experiments manipulating temperature have shown a biomass decrease in some organisms with increasing temperatures. Here we test whether the body size of the Montpellier snake Malpolon monspessulanus from the southeastern Iberian Peninsula is changing and correlated with the increasing temperature in this region during a 39year period (1976â2014). We measured the snoutâvent length (SVL) of vouchers in scientiïŹc collections to check for trends in adult body size at the population level in relation with temperature, while controlling for the age of the individuals (estimated by skeletochronology, nÂŒ141). Given the great ontogenetic variation in body size of the study species, we categorized age in 3 classes: âyoung adultsâ (under 5 years old), âintermediate adultsâ (from 5 to 7 years old), and âold adultsâ (from 8 to 14 years old). By means of linear mixed models, we found a negative relationship between SVL of âold adultsâ and average annual temperature in the region during the lifetime of each individual. Our results indicate that largest and oldest individuals of the Montpellier Snake, that is, males because of strong sexual size dimorphism in this species, disappeared from the study population, and suggest that it occurred in response to rising environmental temperature.Junta de AndalucĂa RNM-25
Quantum Neural Networks for Forecasting Inflation Dynamics
103â106Inflation is a key indicator in the economy that measures the average level of prices of goods and services, being an important ratio in public and private decision-making, so predicting it with precision has always been a concern of economists. This paper makes inflation predictions with different time horizons applying quantum theory through Quantum Neural Networks. The results obtained teach that Quantum Neural Networks overcome the predictive power of the existing models in the previous literature and yields a low-level of errors when predicting any change in the direction of the forecast trend
Maps preserving zeros of a polynomial
Let \A be an algebra and let be a multilinear polynomial
in noncommuting indeterminates . We consider the problem of describing
linear maps \phi:\A\to \A that preserve zeros of . Under certain technical
restrictions we solve the problem for general polynomials in the case where
\A=M_n(F). We also consider quite general algebras \A, but only for
specific polynomials .Comment: 11 pages, accepted for publication in Linear Algebra App
Neural networks for estimating Macro Asset Pricing model in football clubs
The recent crisis caused by COVID-19 directly affected consumption habits and thestability sof financial markets. In particular, the football industry has been hit hard bythis pandemic and therefore has more volatile stock prices. Given this new scenario,further research is needed to accurately estimate the value of the shares of footballclubs. In this paper, we estimate an asset pricing model in football clubs with differentcompositions of risk nature using non-linear techniques of artificial neural networks.Usually, asset pricing models have been estimated with linear methods such as ordi-nary least squares (...
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