In Search of a theory of debt management

A growing literature integrates theories of debt management into models of optimal fiscal policy. One promising theory argues that the composition of government debt should be chosen so that fluctuations in the market value of debt offset changes in expected future deficits. This complete market approach to debt management is valid even when the government only issues non-contingent bonds. A number of authors conclude from this approach that governments should issue long term debt and invest in short term assets. We argue that the conclusions of this approach are too fragile to serve as a basis for policy recommendations. This is because bonds at different maturities have highly correlated returns, causing the determination of the optimal portfolio to be ill-conditioned. To make this point concrete we examine the implications of this approach to debt management in various models, both analytically and using numerical methods calibrated to the US economy. We find the complete market approach recommends asset positions which are huge multiples of GDP. Introducing persistent shocks or capital accumulation only worsens this problem. Increasing the volatility of interest rates through habits partly reduces the size of these simulations we find no presumption that governments should issue long term debt ? policy recommendations can be easily reversed through small perturbations in the specification of shocks or small variations in the maturity of bonds issued. We further extend the literature by removing the assumption that governments every period costlessly repurchase all outstanding debt. This exacerbates the size of the required positions, worsens their volatility and in some cases produces instability in debt holdings. We conclude that it is very difficult to insulate fiscal policy from shocks by using the complete markets approach to debt management. Given the limited variability of the yield curve using maturities is a poor way to substitute for state contingent debt. The result is the positions recommended by this approach conflict with a number of features that we believe are important in making bond markets incomplete e.g allowing for transaction costs, liquidity effects, etc.. Until these features are all fully incorporated we remain in search of a theory of debt management capable of providing robust policy insights.

Elements of algebraic geometry and the positive theory of partially commutative groups

The first main result of the paper is a criterion for a partially commutative group G to be a domain. It allows us to reduce the study of algebraic sets over G to the study of irreducible algebraic sets, and reduce the elementary theory of G (of a coordinate group over G) to the elementary theories of the direct factors of G (to the elementary theory of coordinate groups of irreducible algebraic sets). Then we establish normal forms for quantifier-free formulas over a non-abelian directly indecomposable partially commutative group H. Analogously to the case of free groups, we introduce the notion of a generalised equation and prove that the positive theory of H has quantifier elimination and that arbitrary first-order formulas lift from H to H * F, where F is a free group of finite rank. As a consequence, the positive theory of an arbitrary partially commutative group is decidable.

Rational first integrals in the Darboux theory of integrability in Cn

"Vegeu el resum a l'inici del document del fitxer adjunt."

Solovian and New Growth Theory from the Perspective of Allyn Young on Macroeconomic Increasing Returns

This paper evaluates, from an Allyn Youngian perspective, the neoclassical Solow model of growth and the associated empirical estimates of the sources of growth based on it. It attempts to clarify Young’s particular concept of generalised or macroeconomic “increasing returns” to show the limitations of a model of growth based on an assumption that the aggregate production function is characterised by constant returns to scale but “augmented” by exogenous technical progress. Young’s concept of endogenous, self-sustaining growth is also shown to differ in important respects (including in its policy implications) from modern endogenous growth theory.

On the homotopy theory of spectral categories

"Vegeu el resum a l'inici del document del fitxer adjunt."

The Marginal Productivity Theory Of The Price Of Capital: An Historical Perspective On The Origins Of The Codswallop

Although it might have been expected that, by this point in time, the unacceptability of the marginal productivity theory of the return on capital would be universally agreed, that is evidently not the case. Popular textbooks still propound the dogma to the innocent. This note is presented in the hope that a succinct indication of the origins of the theory it will contribute to a more general appreciation of the unrealistic and illogical nature of this doctrine.

Still More On Why We Should Bury The Marginal Productivity Theory Of The Price Of Capital: A Supplementary Note

The purpose of this note is to supplement the author’s earlier remarks on the unsatisfactory nature of the neoclassical account of how the return on capital is determined. (See Strathclyde Discussion Paper 12-03: “The Marginal Productivity Theory of the Price of Capital: An Historical Perspective on the Origins of the Codswallop”). The point is made via a simple illustration that certain matters which are problematical in neoclassical terms are perfectly straightforward when viewed from a classical perspective. Basically, the marginalist model of the nature of an economic system is not fit for purpose in that it fails to comprehend the essential features of a surplus-producing economic system as distinct from one merely of exchange.

Suppliers of Priors: A Theory of Retailing Inspired by the Market for Chinese Antiquities

Adverse selection may thwart trade between an informed seller, who knows the probability p that an item of antiquity is genuine, and an uninformed buyer, who does not know p. The buyer might not be wholly uninformed, however. Suppose he can perform a simple inspection, a test of his own: the probability that an item passes the test is g if the item is genuine, but only f < g if it is fake. Given that the buyer is no expert, his test may have little power: f may be close to g. Unfortunately, without much power, the buyer's test will not resolve the difficulty of adverse selection; gains from trade may remain unexploited. But now consider a "store", where the seller groups a number of items, perhaps all with the same quality, the same probability p of being genuine. (We show that in equilibrium the seller will choose to group items in this manner.) Now the buyer can conduct his test across a large sample, perhaps all, of a group of items in the seller's store. He can thereby assess the overall quality of these items; he can invert the aggregate of his test results to uncover the underlying p; he can form a "prior". There is thus no longer asymmetric information between seller and buyer: gains from trade can be exploited. This is our theory of retailing: by grouping items together - setting up a store - a seller is able to supply buyers with priors, as well as the items themselves. We show that the weaker the power of the buyer�s test (the closer f is to g), the greater the seller�s profit. So the seller has no incentive to assist the buyer � e.g., by performing her own tests on the items, or by cleaning them to reveal more about their true age. The paper ends with an analysis of which sellers should specialise in which qualities. We show that quality will be low in busy locations and high in expensive locations.

A critical application of securitization theory: overcoming the normative dilemma of writing security

This article addresses the normative dilemma located within the application of `securitization,’ as a method of understanding the social construction of threats and security policies. Securitization as a theoretical and practical undertaking is being increasingly used by scholars and practitioners. This scholarly endeavour wishes to provide those wishing to engage with securitization with an alternative application of this theory; one which is sensitive to and self-reflective of the possible normative consequences of its employment. This article argues that discussing and analyzing securitization processes have normative implications, which is understood here to be the negative securitization of a referent. The negative securitization of a referent is asserted to be carried out through the unchallenged analysis of securitization processes which have emerged through relations of exclusion and power. It then offers a critical understanding and application of securitization studies as a way of overcoming the identified normative dilemma. First, it examines how the Copenhagen School’s formation of securitization theory gives rise to a normative dilemma, which is situated in the performative and symbolic power of security as a political invocation and theoretical concept. Second, it evaluates previous attempts to overcome the normative dilemma of securitization studies, outlining the obstacles that each individual proposal faces. Third, this article argues that the normative dilemma of applying securitization can be avoided by firstly, deconstructing the institutional power of security actors and dominant security subjectivities and secondly, by addressing countering or alternative approaches to security and incorporating different security subjectivities. Examples of the securitization of international terrorism and immigration are prominent throughout.

The longitudinal association between social functioning and theory of mind in first episode psychosis

Introduction. There is some cross-sectional evidence that theory of mind ability is associated with social functioning in those with psychosis but the direction of this relationship is unknown. This study investigates the longitudinal association between both theory of mind and psychotic symptoms and social functioning outcome in first-episode psychosis. Methods. Fifty-four people with first-episode psychosis were followed up at 6 and 12 months. Random effects regression models were used to estimate the stability of theory of mind over time and the association between baseline theory of mind and psychotic symptoms and social functioning outcome. Results. Neither baseline theory of mind ability (regression coefficients: Hinting test 1.07 95% CI 0.74, 2.88; Visual Cartoon test 2.91 95% CI 7.32, 1.51) nor baseline symptoms (regression coefficients: positive symptoms 0.04 95% CI 1.24, 1.16; selected negative symptoms 0.15 95% CI 2.63, 2.32) were associated with social functioning outcome. There was evidence that theory of mind ability was stable over time, (regression coefficients: Hinting test 5.92 95% CI 6.66, 8.92; Visual Cartoon test score 0.13 95% CI 0.17, 0.44). Conclusions. Neither baseline theory of mind ability nor psychotic symptoms are associated with social functioning outcome. Further longitudinal work is needed to understand the origin of social functioning deficits in psychosis.

Women speaking across the Border: The impact of the Border and the conflict on women's health and roles

This research was commissioned by Derry Well Woman and carried out on its behalf by the Institute of Public Health in Ireland in association with the Institute for Conflict Research and Rethink.The research had two distinct aims:- to improve understanding of the impact of the border and of the conflict on both sidesof the border on women’s health- to improve understanding of women’s roles, particularly as they impact on mental health, in post conflict society.- The research was conducted with a view to its recommendations being used to inform the work of the Cross Border Women’  Health Network as well as other cross border health forums or organisations responsible for service planning and delivery.- The findings of this research are based on a series of 31 in-depth interviews and one focus group with women both north and south of the border and on one focus group and six interviews with women who were specifically consulted as service providers.

The Formal Independence of Regulators: A Comparison of 17 Countries and 7 Sectors

This article seeks to explain the pattern of delegation to independent regulatory agencies in Western Europe. Two types of arguments are advanced to explain variations in the formal independence of regulators. Firstly, the need for governments to increase their credible commitment capacity may lead them to delegate regulation to an agency that is partly beyond their direct control. Secondly, delegation may be a response to the political uncertainty problem, which arises when governments are afraid of being replaced by another coalition with different preferences, which could decide to change existing policy choices. In addition, veto players may constitute a functional equivalent of delegation, since they influence policy stability and therefore tend to mitigate both the credibility and the political uncertainty problems. These arguments are consistent with the results of the empirical analysis of the formal independence of regulators in seventeen countries and seven sectors.

Unpacking the cognitive map: the parallel map theory of hippocampal function

In the parallel map theory, the hippocampus encodes space with 2 mapping systems. The bearing map is constructed primarily in the dentate gyrus from directional cues such as stimulus gradients. The sketch map is constructed within the hippocampus proper from positional cues. The integrated map emerges when data from the bearing and sketch maps are combined. Because the component maps work in parallel, the impairment of one can reveal residual learning by the other. Such parallel function may explain paradoxes of spatial learning, such as learning after partial hippocampal lesions, taxonomic and sex differences in spatial learning, and the function of hippocampal neurogenesis. By integrating evidence from physiology to phylogeny, the parallel map theory offers a unified explanation for hippocampal function.