57,334 research outputs found

    Pseudo-Deterministic Streaming

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    A pseudo-deterministic algorithm is a (randomized) algorithm which, when run multiple times on the same input, with high probability outputs the same result on all executions. Classic streaming algorithms, such as those for finding heavy hitters, approximate counting, ?_2 approximation, finding a nonzero entry in a vector (for turnstile algorithms) are not pseudo-deterministic. For example, in the instance of finding a nonzero entry in a vector, for any known low-space algorithm A, there exists a stream x so that running A twice on x (using different randomness) would with high probability result in two different entries as the output. In this work, we study whether it is inherent that these algorithms output different values on different executions. That is, we ask whether these problems have low-memory pseudo-deterministic algorithms. For instance, we show that there is no low-memory pseudo-deterministic algorithm for finding a nonzero entry in a vector (given in a turnstile fashion), and also that there is no low-dimensional pseudo-deterministic sketching algorithm for ?_2 norm estimation. We also exhibit problems which do have low memory pseudo-deterministic algorithms but no low memory deterministic algorithm, such as outputting a nonzero row of a matrix, or outputting a basis for the row-span of a matrix. We also investigate multi-pseudo-deterministic algorithms: algorithms which with high probability output one of a few options. We show the first lower bounds for such algorithms. This implies that there are streaming problems such that every low space algorithm for the problem must have inputs where there are many valid outputs, all with a significant probability of being outputted

    The Number of Firms and the Politics of Export Subsidy

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    The purpose of this paper is to present a framework to understand that the government's implementation of export subsidy is influenced by the political pressure from the home firms which can bear the costs of forming and maintaining a lobby in order to overcome a free-rider problem associated with lobbying. When the number of the foreign firms is large in comparison with that of the home firms, the home firms can organize a lobby group more easily and lobby for higher export subsidy. The implementation of politically optimal export subsidy can make the domestic social welfare far worse than when the free trade is maintained by a multilateral agreement which prohibit export subsidies.Lobby formation, Political contribution, Export subsidy, Multilateral agreements

    Firm Heterogeneity, Contract Enforcement, and the Industry Dynamics of Offshoring

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    We develop an endogenous growth model to study the long run consequences of offshoring with firm heterogeneity and incomplete contracts. In so doing, we model offshoring as the geographical fragmentation of a firm’s production chain between a home upstream division and a foreign downstream one. On the positive side, we show that, when contracts are incomplete, the possibility of offshoring has favorable implications for economic growth. Yet, offshoring induced by a higher bargaining power of the upstream division can hamper growth: while there is always a positive correlation between upstream bargaining weight and offshoring activities, there is a non-monotonic relationship between these and growth. Whether offshoring with incomplete contracts also increases consumption depends on firm heterogeneity. On the normative side, we show that, whereas with complete contract efficiency is restored through a subsidy to R&D only, with incomplete contracts a production subsidy to offshored upstream divisions is needed too.Offshoring, Heterogeneous Firms, Incomplete Contracts, Growth, Industry Dynamics

    Neutrino Parameters, Abelian Flavor Symmetries, and Charged Lepton Flavor Violation

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    Neutrino masses and mixings have important implications for models of fermion masses, and, most directly, for the charged lepton sector. We consider supersymmetric Abelian flavor models, where neutrino mass parameters are related to those of charged leptons and sleptons. We show that processes such as \tau to \mu\gamma, \mu to e\gamma and \mu-e conversion provide interesting probes. In particular, some existing models are excluded by current bounds, while many others predict rates within reach of proposed near future experiments. We also construct models in which the predicted rates for charged lepton flavor violation are below even the proposed experimental sensitivities, but argue that such models necessarily involve loss of predictive power.Comment: 27 pages, refs added, published versio

    Trade Barriers As Bargaining Outcomes

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    Whether bilateral trade barrier data conform with the Grossman-Helpman (1995) model’s predictions about “trade talks” is examined in this article. A simple form of the prediction from the model is tested. Bilateral US-Japan and US-EU data from the 1990s are employed. The results are the first in the literature.Trade talks equilibrium; Nontariff barriers;
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