Haefliger structures and symplectic/contact structures

For some geometries including symplectic and contact structures on an n-dimensional manifold, we introduce a two-step approach to Gromov's h-principle. From formal geometric data, the first step builds a transversely geometric Haefliger structure of codimension n. This step works on all manifolds, even closed. The second step, which works only on open manifolds and for all geometries, regularizes the intermediate Haefliger structure and produces a genuine geometric structure. Both steps admit relative parametric versions. The proofs borrow ideas from W. Thurston, like jiggling and inflation. Actually, we are using a more primitive jiggling due to R. Thom.Comment: To appear in Journal de l'Ecole Polytechniqu

When Sheep Shop: Measuring Herding Effects in Product Ratings with Natural Experiments

As online shopping becomes ever more prevalent, customers rely increasingly on product rating websites for making purchase decisions. The reliability of online ratings, however, is potentially compromised by the so-called herding effect: when rating a product, customers may be biased to follow other customers' previous ratings of the same product. This is problematic because it skews long-term customer perception through haphazard early ratings. The study of herding poses methodological challenges. In particular, observational studies are impeded by the lack of counterfactuals: simply correlating early with subsequent ratings is insufficient because we cannot know what the subsequent ratings would have looked like had the first ratings been different. The methodology introduced here exploits a setting that comes close to an experiment, although it is purely observational---a natural experiment. Our key methodological device consists in studying the same product on two separate rating sites, focusing on products that received a high first rating on one site, and a low first rating on the other. This largely controls for confounds such as a product's inherent quality, advertising, and producer identity, and lets us isolate the effect of the first rating on subsequent ratings. In a case study, we focus on beers as products and jointly study two beer rating sites, but our method applies to any pair of sites across which products can be matched. We find clear evidence of herding in beer ratings. For instance, if a beer receives a very high first rating, its second rating is on average half a standard deviation higher, compared to a situation where the identical beer receives a very low first rating. Moreover, herding effects tend to last a long time and are noticeable even after 20 or more ratings. Our results have important implications for the design of better rating systems.Comment: Submitted at WWW2018 - April 2018 (10 pages, 6 figures, 6 tables); Added Acknowledgement

Adult siblings who have a brother or sister with autism: between-family and within-family variations in sibling relationships

Prior research on the sibling relationship in the context of autism spectrum disorder (ASD) has included only one sibling per family. We used multi-level modeling to examine aspects of the sibling relationship in 207 adults who have a brother or sister with ASD from 125 families, investigating variability in sibling relationship quality and pessimism within and between families. We found that there was greater variability in aspects of the sibling relationship with the brother or sister with ASD within families than between families. Sibling individual-level factors were associated with positive affect in the sibling relationship, while family-level factors were associated with the sibling’s pessimism about their brother or sister’s future. The findings illustrate the unique experiences of siblings within families.This research was supported in part by a grant from the National Institute on Aging (R01 AG08768) to Marsha Mailick and support from the Waisman Center Core Grant (U54 HD090256). The authors are appreciative of the opportunity to collaborate with Dr. Mailick. (R01 AG08768 - National Institute on Aging; U54 HD090256 - Waisman Center Core Grant)Accepted manuscript2019-12-3

Modelling Behavioral Heterogeneity.

If one wants to get rid of the paradoxes pointed out by Hildenbrand (1998) and B. de Villemeur (1999), one needs to reformulate Grandmont's (1992) notion of behavioral heterogeneity such as to get exact insensitivity of the aggregate budget share function with respect to changes in prices and income, instead of a mere approximate insensitivity. Here, we propose a non parametric set-up such that, if the population is distributed according to some ``uniform'' measure, the aggregate budget share function is constant. This exact insensitivity is not explained by any insensitivity property at the micro-economic level, but rather by a perfect ``balancing effect''. We then discuss the economic interpretation of some concrete examples illustrating our theory.Aggregation of demand, behavioral heterogeneity, large economy, Law of Demand, Insensitivity of market budget shares.

Electoral Control when Policies are for Sale

This article analyses the dynamics of electoral promises, building on an electoral competition model with endogenous policies. It extends the Grossman-Helpman (1994) model [Grossman G., Helpman E. [1994], "Protection for sale", American Economic Review, 84, 4, 833-850] to include sanctions from the electorate and lobbies when the incumbent does not satisfy the expected performance she promised to deliver. This framework allows to deal with the intertemporal dimension needed to understand the prevalent cycle of promises, disappointment, new promises, new disappointment ….lobbies, promises, elections, electoral competition, lies

Ethical relativism vs absolutism : research implications

Purpose &ndash; The constructs of relativism and absolutism have a significant role to play in the development of ethical theory; however, they are commonly simplified in their depictions and are philosophically more complex than we give them credit for. The purpose of this paper is to undertake an in-depth examination of ethical relativity and ethical absolutism before concluding with a discussion of which research implications warrant further investigation.Design/methodology/approach &ndash; A descriptive, historical, anthological approach has been taken.Findings &ndash; Ethical relativism is regrettably subject to a proliferation of related terminology and, in many instances with different meanings ascribed to similar terms. In addition, ethical relativity appears to attract different research perspectives that are heavily dependent on their academic origins. A clear distinction needs to be made between ethical and situational relativity. It is suggested that relativism is present in the process of moral justification and that ethical relativism should be analyzed from three levels: the individual level, the role and group level, and the cultural levels. The over-riding objection to ethical relativism rests on the consequences of accepting relativism, which undermines the existence and strength of global moral standards and the inherent positioning of ethical absolutism. Absolutism does not deny the existence of multiple moral practices evident around the world, but proposes that variations in ethical actions could still be rooted in common universal moral standards based on our requirements as human beings and the necessities of long-term survival.Research limitations/implications &ndash; The ensuing discussions of relativism and absolutism open up a rich vein of research opportunities and suggest caution is required in regard to research methodologies. From a methodological perspective, care needs to be taken. For example, using hypothetical ethical dilemmas that are often unrelated to a specific industry or cultural setting has resulted in many researchers observing situational relativity rather than true ethical relativity.Originality/value &ndash; This paper specifically examines whether there are differences in underlying and basic moral standards even though similarities in ethical behaviour have been determined, or whether differing ethical actions could, as the absolutists believe, originate from common universal standards despite apparent differences in perceptions and actions across cultures.<br /