A Chart-Parsing Algorithm for Efficient Semantic Analysis

In some contexts, well-formed natural language cannot be expected as input to information or communication systems. In these contexts, the use of grammar-independent input (sequences of uninflected semantic units like e.g. language-independent icons) can be an answer to the users' needs. A semantic analysis can be performed, based on lexical semantic knowledge: it is equivalent to a dependency analysis with no syntactic or morphological clues. However, this requires that an intelligent system should be able to interpret this input with reasonable accuracy and in reasonable time. Here we propose a method allowing a purely semantic-based analysis of sequences of semantic units. It uses an algorithm inspired by the idea of ``chart parsing'' known in Natural Language Processing, which stores intermediate parsing results in order to bring the calculation time down. In comparison with using declarative logic programming - where the calculation time, left to a prolog engine, is hyperexponential -, this method brings the calculation time down to a polynomial time, where the order depends on the valency of the predicates.Comment: 7 pages, 1 figure, LaTeX 2e using COLACL and EPSF packages. Proceedings of the 19th International Conference on Computational Linguistics (COLING 2002), Taipei, Republic of China (Taiwan), 24 Aug. - 1 Sept. 200

Trade policy on a country basis and multilateral arrangements: The case of Uruguay

This paper sheds some light on two issues related to recent the multilateral trade agreements (Ronda Uruguay of GATT and the creation of WTO). First, are they binding for the design of trade policies in Uruguay? Second, how have they posed restrictions on these policies? In the first chapter a revision of the trade policies developed in Uruguay along the last decades is done, with a historic perspective. It is there concluded that Uruguay has had a continuous unilateral pro-liberalization position. The description of government institutions and private lobby groups is used in the second section to analyze the process. There is enough evidence supporting the hypothesis that the trade liberalization process can be thought of as a political equilibrium between government and private lobby groups. Finally, the paper concludes that multilateral agreements are increasingly determining the characteristics of trade policies in Uruguay.

How and when a unilateral trade reform could be a political equilibrium

In the paper the endogenous trade model follows the Grosman and Helpman (1994 y 1995) tradition. The structure of the economy is characterised by a specific factor trade model and consumers' preferences are quasilinears. Owners of specific factors all are organised in lobby groups and the ownership are very concentrated.The available options to the government are mantain the trade policy status quo or implement an opening trade reform. Lobbys group influence this discretional government with income contribution taking into account its own objective function. The equilibrium of the game is studied in two differents situations: without exceptions in the trade liberalisation; with the presence of sector exception list. It is shown that a commercial opening that is not a political equilibrium (it is not incentives compatible) when the government wants to make it in general, however can be so if the government is able to isolate certain sectors from the international competition, through long periods of adjustment (given by gradual policies or the existence of exceptions list). The results are illustrated applying the model to the case of a trade reform in a developing country (Uruguay).

Endogenous number of lobby groups in a specific factor trade model

The basic goal of this paper is to develop an endogenous trade policy model in the Grossman and Helpman (1994) tradition that could endogenise the number of lobby groups in the economy. The game has three stages. In the first stage, the consumer that owns a specific factor decides whether to organise or not in pressure groups. In the second one, the lobbies (organised groups of consumers) select the contributions (income transfers) they are willing to make to influence the government's actions. Finally, in a third stage of the game the government establishes the trade policy. This chapter highlights two main results. The first one is that contribution is a dominant strategy for each lobby group, thus the sub-game perfect equilibrium implies all the lobby groups being active (L=N). The second one is related with the welfare evaluation of this equilibrium. It is well known in the literature that this equilibrium is efficient (in a Pareto sense) but it is also important to analyse what happen when only the lobby welfare is considered. The conclusion is that being organised and defending a particular interest is better than not being organised, given that the others are not organised (or only some are), because it is possible to obtain an advantage in the political relationship with the government. On the other hand, since the other antagonic groups (one or some) are organised in lobbies, it is possible to reduce the damage from the distortions created by their influence on the government’s actions. An implication of this result is that many times in societies with a multiplicity of specific interests organised corporately, typically all finish in a worst situation than if they were not organised, arriving to a prisoner's dilemma outcome, if only the lobby’s welfare is considered.

Endogenous trade policy and political contributions in a standard-trade model (HOS trade model)

The paper developed a political economy model about endogenous trade policy along the lines of the well known contribution of Grossman and Helpman (1994). In our case the structure of the economy is standard (neoclassical trade model instead of the specific factor trade model of the original paper) and more general (preferences are not quasilinear). In this new environment an equilibrium of the game is derived. Two basic proposition resume the results related to the level of the trade policy instruments set by the policy makers and the political contribution made by the active group of consumers (lobbies). This new general result is analysed in a particular small economy abundant in a factor different from labor, e.g. natural resources.Three cases are studied to present the results of the two general propositions according with the different active lobby in the contribution game :labor unions that allow the income contribution of workers to influence the trade policy; factor owners associations that allow the income contribution of the others consumers in the other extreme of the income distribution; contributions of both types of consumers workers and owners.

How and When a Unilateral Trade Reform Could be a Political Equilibrium

In the paper the endogenous trade model follows the Grosman and Helpman (1994 y 1995) tradition. The structure of the economy is characterised by a specific factor trade model and consumers' preferences are quasilinears. Owners of specific factors all are organised in lobby groups and the ownership are very concentrated.The available options to the government are mantain the trade policy status quo or implement an opening trade reform. Lobbys group influence this discretional government with income contribution taking into account its own objective function. The equilibrium of the game is studied in two differents situations: without exceptions in the trade liberalisation; with the presence of sector exception list. It is shown that a commercial opening that is not a political equilibrium (it is not incentives compatible) when the government wants to make it in general, however can be so if the government is able to isolate certain sectors from the international competition, through long periods of adjustment (given by gradual policies or the existence of exceptions list).