4,851 research outputs found
Money and Price Posting under Private Information
We study price posting with undirected search in a search-theoretic monetary model with divisible money and divisible goods. Ex ante homogeneous buyers experience match specific preference shocks in bilateral trades. The shocks follow a continuous distribution and the realization of the shocks is private information. We show that generically there exists a unique price posting monetary equilibrium. In equilibrium, each seller posts a continuous pricing schedule that exhibits quantity discounts. Buyers spend only when they have high enough preferences. As their preferences are higher, they spend more till they become cash constrained. Since inflation reduces the future purchasing power of money and the value of retaining money, buyers tend to spend their money faster in response to higher inflation. In particular, more buyers choose to spend money and buyers spend on average a higher fraction of their money. The model naturally captures the hot potato effect of inflation along both the intensive margin and the extensive margin.Economic models; Inflation and prices
Un 3-polyGEM de cohomologie modulo 2 nilpotente
In 1983, C. McGibbon and J. Neisendorfer have given a proof for one
conjecture in J.-P. Serre's famous paper (1953). In 1985, another proof was
given by J. Lannes and L. Schwartz.
Since then, one considers a more general conjecture: if the reduced mod 2
cohomology of any 1-connected polyGEM is of finite type and is not trivial,
then it contains at least one element of infinite height, i.e., non nilpotent.
This conjecture has been verified in several special situations, more
precisely, by Y. Felix, S. Halperin, J.-M. Lemaire and J.-C. Thomas in 1987, by
J. Lannes and L. Schwartz in 1988, and by J. Grodal in 1996.
In this note, we construct an example, for which this conjecture fails.Comment: accepted in les Annales de l'Institut Fourie
Topological Imbert-Fedorov shift in Weyl semimetals
The Goos-H\"anchen (GH) shift and the Imbert-Fedorov (IF) shift are optical
phenomena which describe the longitudinal and transverse lateral shifts at the
reflection interface, respectively. Here, we report the GH and IF shifts in
Weyl semimetals (WSMs) - a promising material harboring low energy Weyl
fermions, a massless fermionic cousin of photons. Our results show that GH
shift in WSMs is valley-independent which is analogous to that discovered in a
2D relativistic material - graphene. However, the IF shift has never been
explored in non-optical systems, and here we show that it is valley-dependent.
Furthermore, we find that the IF shift actually originates from the topological
effect of the system. Experimentally, the topological IF shift can be utilized
to characterize the Weyl semimetals, design valleytronic devices of high
efficiency, and measure the Berry curvature
Online/Offline Blind Signature
AbstractThe processing ablity and response speed of the wireless communication terminals are limited, common signatures become the bottleneck to the development of the wireless networks. For that problem, based on the characteristics of the blind signature, the online/offline blind signature is given in this paper which incorporates with the optimal online/offline signature. Most computations are finished before the blind message is given, after that, only a few operations are needed. The performance analysis is also given in this paper, the new signature scheme can be applied to the security of wireless network, it protect the users’ privacy efficiently
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Visualizing Morphogenesis through Instability Formation in 4-D Printing.
Heterogeneous growth in a myriad of biological systems can lead to the formation of distinct morphologies during the maturation processes of different species. We demonstrate that the distinct circumferential buckling observed in pumpkins can be reproduced by a core-shell barrel structure using four-dimensional (4D) printing, taking advantage of digital light processing (DLP)-based three-dimensional (3D) printing and stimulus-responsive hydrogels. The mechanical mismatch between the stiff core and compliant shell results in buckling instability on the surface. The initiation and development of the buckling are governed by the ratio of core/shell radius, the ratio of core/shell swelling ratios, and the mismatch between the core and shell in stiffness. Furthermore, the rigid core not only acts as a source of circumferential confinement but also sets a boundary at the poles of the entire structure. The heterogeneous structures with controllable buckling geometrically and structurally behave much like plants' fruits. This replicates the biological morphologic change and elucidates the general mechanism and dynamics of the complex instability formation of heterogeneous 3D objects
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