Lorentzian homogeneous spaces admitting a homogeneous structure of type T1+T3

We show that a Lorentzian homogeneous space admitting a homogeneous structure of type T1 + T3 is either a (locally) symmetric space or a singular homogeneous plane wave.Comment: 7 pages, Latex2e, a small note and a reference adde

Analyzing aggregate real exchange rate persistence through the lens of sectoral data.

In this paper we analyze the persistence of aggregate real exchange rates (RERs) for a group of EU-15 countries by using sectoral data. The tight relation between aggregate and sectoral persistence recently investigated by Mayoral (2008) allows us to decompose aggregate RER persistence into the persistence of its different subcomponents. We show that the distribution of sectoral persistence is highly heterogeneous and very skewed to the right, and that a limited number of sectors are responsible for the high levels of persistence observed at the aggregate level. We use quantile regression to investigate whether the traditional theories proposed to account for the slow reversion to parity (lack of arbitrage due to nontradibilities or imperfect competition and price stickiness) are able to explain the behavior of the upper quantiles of sectoral persistence. We conclude that pricing to market in the intermediate goods sector together with price stickiness have more explanatory power than variables related to the tradability of the goods or their inputs.PPP puzzle, real exchange rates, persistence, heterogeneous dynamics, aggregation bias, nontradability, imperfect competition, pricing-to-market.

Formalization of Universal Algebra in Agda

In this work we present a novel formalization of universal algebra in Agda. We show that heterogeneous signatures can be elegantly modelled in type-theory using sets indexed by arities to represent operations. We prove elementary results of heterogeneous algebras, including the proof that the term algebra is initial and the proofs of the three isomorphism theorems. We further formalize equational theory and prove soundness and completeness. At the end, we define (derived) signature morphisms, from which we get the contravariant functor between algebras; moreover, we also proved that, under some restrictions, the translation of a theory induces a contra-variant functor between models.Fil: Gunther, Emmanuel. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gadea, Alejandro Emilio. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pagano, Miguel Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentin

Cyclic metric Lie groups

Cyclic metric Lie groups are Lie groups equipped with a left-invariant metric which is in some way far from being biinvariant, in a sense made explicit in terms of Tricerri and Vanhecke's homogeneous structures. The semisimple and solvable cases are studied. We extend to the general case, Kowalski-Tricerri's and Bieszk's classifications of connected and simply-connected unimodular cyclic metric Lie groups for dimensions less than or equal to five

Cyclic homogeneous Riemannian manifolds

In spin geometry, traceless cyclic homogeneous Riemannian manifolds equipped with a homogeneous spin structure can be viewed as the simplest manifolds after Riemannian symmetric spin spaces. In this paper, we give some characterizations and properties of cyclic and traceless cyclic homogeneous Riemannian manifolds and we obtain the classification of simply-connected cyclic homogeneous Riemannian manifolds of dimension less than or equal to four. We also present a wide list of examples of non-compact irreducible Riemannian $3$-symmetric spaces admitting cyclic metrics and give the expression of these metrics

Schadenfreude is higher in real-life situations compared to hypothetical scenarios

Schadenfreude (i.e., the pleasure derived from another's misfortune) has been widely studied by having participants imagine how they would feel in hypothetical scenarios describing another person's pain or misfortune. However, research on affective forecasting shows that self-judgments of emotions are inaccurate in hypothetical situations. Here we show a study in which we first presented a hypothetical schadenfreude situation and few months later, due to an exceptional circumstance, the situation turned out to happen in reality. This fortuitous circumstance allowed us to compare people's imagined emotional reactions with their actual feelings. Results showed that schadenfreude was higher in the real situation than in the hypothetical one. More importantly, participants used different proxies to predict their emotional reaction: while out-group dislike served as a proxy of schadenfreude in both types of scenario, the degree of in-group identification also increased schadenfreude in those who had experienced the real event, arguably a mechanism to promote positive self-evaluation. These results highlight the importance of assessing schadenfreude in the heat of the moment.Fil: González Gadea, María Luz. Universidad Favaloro; Argentina. Universidad Torcuato Di Tella; Argentina. Instituto de Neurología Cognitiva; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ibañez, Agustin Mariano. Universidad Adolfo Ibañez; Chile. Universidad Autónoma Del Caribe; Colombia. Instituto de Neurología Cognitiva; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sigman, Mariano. Universidad Torcuato Di Tella; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Measuring the external risk in the United Kingdom

This paper aims to describe the evolution of the external risk in the United Kingdom between 1961 and 2008. We first present a theoretical description of the risk indicator. Then, we calculate this measure for the British economy in the period of study. In general, the results reveal a very small increase of external risk. Finally, the relationship between the two dimensions of external risk: trade openness and external volatility is analysed.trade openness, terms of trade volatility, external risk, United Kingdom