Amphorae from the Roman Theatre of Olisipo (Lisbon, Portugal): 2001-2006 campaigns

O texto que se dá à estampa consiste no estudo das ânforas romanas exumadas nas intervenções arqueológicas realizadas no teatro romano de Lisboa nas campanhas de 2001, 2005 e 2006. Trata-se de um conjunto relativamente amplo e tipologicamente diversificado recolhido em contextos arqueológicos relacionados com a edificação e remodelação do edifício. Estes contentores testemunham, em Olisipo, a importação de produtos alimentares de vá- rios locais do império desde meados do século II a.C. até ao terceiro quartel do século I d.C., constituindo-se como importantes indicadores para o estudo da dinâmica comercial de Olisipo.This text consists in the study of the Roman amphorae recovered in the archaeological excavations accomplished in the Roman theatre of Lisbon in the 2001, 2005 and 2006 campaigns. It is a relatively wide and typologically diversified set, collected in archaeological contexts related with the construction and remodelling of the theatre. These containers testify, in Olisipo, the importation of alimentary products from several places of the empire from the middle of the 2nd century B.C. to the third quarter of the 1st century A.D., representing important indicators for the study of the commercial dynamics of Olisipo

Olisipo (Lisboa, Portugal) y su lugar en el comercio romano

Although usually considered the most important city of Lusitania - after Augusta Emerita - and the main maritime harbour of the whole Atlantic peninsular façade, there remains a generalized absence of studies that highlight the role that Olisipo played in the most western of the Roman provinces’ economy and commercial relations. This work aims to address that absence, by focusing on the research on Olisipo, located at the Tagus estuary, during the period encompassing the Republic and the Principate, and based on the study of amphorae. The dataset resulting from the analysis of the amphorae from Lisbon discloses the existence of a vast network of commercial relations with the diverse areas of the Mediterranean throughout all of the considered chronology, thus revealing a cosmopolitan city, with an active and central role in the complex commercial exchanges of the West of Iberian Peninsula with the rest of the Roman Empire. These results underline Olisipo’s importance as a trading post in the Atlantic coast during the Roman period, a role that has been recognized long ago, allowing to draw in a more accurate way how the city’s economic history was shaped.Aunque generalmente se la considera la ciudad más importante de Lusitania, después de la capital provincial Augusta Emerita, y como el principal puerto marítimo de toda la fachada peninsular del Atlántico, todavía hay un panorama general de falta de estudios que muestren el papel destacado desempeñado por Olisipo en la economía y las relaciones comerciales de Lusitania. Este trabajo, basado en el estudio de las ánforas de la República y el Principado, busca precisamente llenar este vacío que existe actualmente en la investigación de Olisipo. El conjunto de datos obtenidos del análisis de las ánforas de Lisboa revela la existencia de una vasta rede de enlaces comerciales con las áreas más diversas del Mediterráneo a lo largo de la diacronía considerada, revelando una ciudad cosmopolita con un papel activo y central en los complejos intercambios comerciales del occidente peninsular con el resto del Imperio Romano. Estos resultados subrayan el papel de Olisipo y su puerto como un importante puesto comercial en la costa atlántica durante el período romano, un papel que ha sido reconocido desde hace mucho tiempo, permitiendo ahora una delimitación más cercana de cómo y con qué ritmos se formó la historia económica de esta ciudad.info:eu-repo/semantics/publishedVersio

Endogenous debt constraints in collateralized economies with default penalties

In infinite horizon financial markets economies, competitive equilibria fail to exist if one does not impose restrictions on agents' trades that rule out Ponzi schemes. When there is limited commitment and collateral repossession is the unique default punishment, Araujo, Páscoa and Torres-Martínez (2002) proved that Ponzi schemes are ruled out without imposing any exogenous/endogenous debt constraints on agents' trades. Recently Páscoa and Seghir (2009) have shown that this positive result is not robust to the presence of additional default punishments. They provide several examples showing that, in the absence of debt constraints, harsh default penalties may induce agents to run Ponzi schemes that jeopardize equilibrium existence.The objective of this paper is to close a theoretical gap in the literature by identifying endogenous borrowing constraints that rule out Ponzi schemes and ensure existence of equilibria in a model with limitedcommitment and (possible) default. We appropriately modify the definition of finitely effective debt constraints, introduced by Levine and Zame (1996) (see also Levine and Zame (2002)), to encompass models with limited commitment, default penalties and collateral. Along this line, we introduce in the setting of Araujo, Páscoa and Torres-Martínez (2002), Kubler and Schmedders (2003) and Páscoa and Seghir (2009) the concept of actions with finite equivalent payoffs. We show that, independently of the level of default penalties, restricting plans to have finite equivalent payoffs rules out Ponzi schemes and guarantees the existence of an equilibrium that is compatible with the minimal ability to borrow and lend that we expect in our model.An interesting feature of our debt constraints is that they give rise to budget sets that coincide with the standard budget sets of economies having a collateral structure but no penalties (as defined in Araujo,Páscoa and Torres-Martínez (2002)). This illustrates the hidden relation between finitely effective debt constraints and collateral requirements.

Existence and Uniqueness of a Fixed-Point for Local Contractions

This paper proves the existence and uniqueness of a fixed-point for local contractions without assuming the family of contraction coefficients to be uniformly bounded away from 1. More importantly it shows how this fixed-point result can apply to study existence and uniqueness of solutions to some recursive equations that arise in economic dynamics.

Cournot–Nash equilibria in continuum games with non-ordered preferences.

In the usual framework of continuum games with externalities, we substantially generalize Cournot–Nash existence results [Balder, A unifying approach to existence of Nash equilibria, Int. J.Game Theory 24 (1995) 79–94; On the existence of Cournot–Nash equilibria in continuum games, J. Math. Econ. 32 (1999) 207–223; A unifying pair of Cournot–Nash equilibrium existence results, J. Econ. Theory 102 (2002) 437–470] to games with possibly non-ordered preferences, providing a continuum analogue of the seminal existence results by Mas-Colell [An equilibrium existence theorem without complete or transitive preferences, J. Math. Econ. 1 (1974) 237–246], Gale and Mas-Colell [An equilibrium existence theorem for a general model without ordered preferences, J. Math. Econ. 2 (1975) 9–15], Shafer and Sonnenschein [Equilibrium in abstract economies without ordered preferences, J. Math. Econ. 2 (1975) 345–348], Borglin and Keiding [Existence of equilibrium actions and of equilibrium: a note on the “new” existence theorems, J. Math. Econ. 3 (1976) 313–316] and Yannelis and Prabhakar [Existence of maximal elements and equilibria in linear topological spaces, J. Math. Econ. 12 (1983) 233–245].Pure Cournot–Nash equilibrium; Continuum games; Non-ordered preferences; Feeble topology;

Large economies with differential information and without free disposal.

We consider exchange economies with a continuum of agents and differential information about finitely many states of nature. It was proved in Einy, Moreno, and Shitovitz (2001) that if we allow for free disposal in the market clearing (feasibility) constraints then an irre- ducible economy has a competitive (or Walrasian expectations) equilibrium, and moreover, the set of competitive equilibrium allocations coincides with the private core. However when feasibility is defined with free disposal, competitive equilibrium allocations may not be in- centive compatible and contracts may not be enforceable (see e.g. Glycopantis, Muir, and Yannelis (2002)). This is the main motivation for considering equilibrium solutions with exact feasibility. We first prove that the results in Einy, Moreno, and Shitovitz (2001) are still valid without free-disposal. Then, motivated by the issue of contracts’ execution, we adapt the incentive compatibility property introduced in Krasa and Yannelis (1994) and we prove that every Pareto optimal exact feasible allocation is incentive compatible, implying that contracts of competitive or core allocations are enforceable.Large exchange economies; Incentive Compatibility; Competitive and Core Allocations; Differential information;

Endogenous Transaction Costs

The paper proposes an alternative general equilibrium formulation of financial asset economies with transactions costs. Transaction costs emerge endogenously at equilibrium and reflect agents decisions of intermediating financial activities at the expense of providing labor services. An equilibrium is shown to exist in the case of real asset structures.

Competitive equilibria in infinite-horizon collateralized economies with default penalties

Araújo, Páscoa and Torres-Martinez (2002) have shown that, without imposing either debt constraints or transversality conditions, Ponzi schemes are ruled out in infinite horizon economies with default when collateral is the only mechanism that partially secures loans. Páscoa and Seghir (2008) subsequently show that Ponzi schemes may reappear if, additionally to the seizure of the collateral, there are sufficiently harsh default penalties assessed (directly in terms of utility) against the defaulters. They also claim that if default penalties are moderate then Ponzi schemes are ruled out and existence of a competitive equilibrium is ensured. The objective of this paper is two fold. First, contrary to what is claimed by Páscoa and Seghir (2008), we show that moderate default penalties do not always prevent agents to run a Ponzi scheme. Second, we provide an alternative condition on default penalties that is sufficient to rule out Ponzi schemes and ensure the existence of a competitive equilibrium.