The completion of security markets

Abstract In this article we study the completion by options of a two-period security market in which the space of marketed securities is a subspace X of . Although there are important results about the completion (by options) Z of X, the problem of the determination of Z in its general form is still open. In this paper we solve this problem by determining a positive basis of Z. This method of positive bases simplifies the theory of security markets and also answers other open problems of this theory. In the classical papers of this subject, call and put options are taken with respect to the riskless bond 1 of . In this article we generalize this theory by taking call and put options with respect to different risky vectors u from a fixed vector subspace U of . This generalization was inspired by certain types of exotic option in finance. Mathematics Subject Classification (2000): 46B40, 46A35, 91B28, 91B30 Journal of Economic Literature Classification: G190, D520     

NONREPLICATION OF OPTIONS

In this paper, we study the replication of options in security markets X with a finite number of states. Specifically, we prove that in security markets without binary vectors, for any portfolio, at most m ? 3 options can be replicated where m is the number of states. This is an essential improvement of the result of Baptista where it is proved that the set of replicated options is of measure zero. Additionally, we extend the results of Aliprantis and Tourky on the nonreplication of options by generalizing their condition that markets are strongly resolving. Our results are based on the theory of lattice‐subspaces and positive bases.     

Knowledge management in enterprises: a research agenda

Knowledge management (KM) is an emerging area, which is gaining interest by both enterprises and academics. The effective implementation of a KM strategy is considering as a ‘must’ and as a precondition of success for contemporary enterprises, as they enter the era of the knowledge economy. However, the field of KM has been slow in formulating a universally accepted methodology, due to the many pending issues that have to be addressed. This paper attempts to propose a novel taxonomy for KM research by co‐instantaneously presenting the current status with some major themes of KM research. The discussion presented on these issues should be of value to researchers and practitioners. Copyright © 2005 John Wiley & Sons, Ltd.     

Risk informed decision making in land use planning

The objective of the paper is to present a multicriteria decision methodology for supporting decisions about patterns of land development in the vicinity of major hazard installations. The proposed methodology is based on the paradigm of Multicriteria Decision Analysis and aims at integrating the results of risk analysis of major hazard installations with models for land use planning. The methodology possesses two main features: it is interactive and it does not require assessment of value tradeoffs prior to assessing the most preferred land use pattern. The latter is achieved by determining the efficient set of land use patterns by means of a dynamic programming-based algorithm. The proposed methodology and the use of the efficient set of solutions in supporting land use planning decisions are demonstrated through an application. Four criteria are used in the application, three referring to risk and one to the benefits of alternative land use patterns, although the methodology can accept any number of decision criteria as well as various types of land development. A computerized decision support system has been developed to implement the proposed methodology.     

The implied liquidity premium for equities

Over the long term, the returns on smaller stocks are likely to be higher than the returns on larger stocks. This phenomenon has been called size effect, and a number of explanations have been proposed to account for it. Here we show that the difference in return between the larger and the smaller stocks can be accounted for by a liquidity premium for the smaller stocks, and we estimate the value of this premium using structural parameters for the capital distribution of the U.S. stock market during the 1990s The authors wish to express their gratitude to an anonymous referee for a very thorough and incisive reading, as well as for many constructive suggestions that have significantly improved this paper. The authors wish to express their gratitude to an anonymous referee for a very thorough and incisive reading, as well as for many constructive suggestions that have significantly improved this paper.     

Quantile regression analysis of hedge fund strategies

Extending previous work on hedge fund pricing, this paper introduces the idea of modelling the conditional quantiles of hedge fund returns using a set of risk factors. Quantile regression analysis provides a way of understanding how the relationship between hedge fund returns and risk factors changes across the distribution of conditional returns. We propose a Bayesian approach to model comparison which provides posterior probabilities for different risk factor models that can be used for model averaging. The most relevant risk factors are identified for different quantiles and compared with those obtained for the conditional expectation model. We find differences in factor effects across quantiles of returns, which suggest that the standard conditional mean regression method may not be adequate for uncovering the risk-return characteristics of hedge funds. We explore potential economic impacts of our approach by analysing hedge fund single strategy return series and by constructing style portfolios.     

Maximal submarkets that replicate any option

In this article we study the replication of options in security markets X with a finite number of states. Specifically, we study the existence of maximal submarkets (subspaces) Y of X so that any option written on the elements of Y is replicated by a marketed asset x of X. So inside these subspaces the pricing problem is simple because any option is priced by the replicating portfolio. Using the theory of lattice-subspaces and positive bases developed by Polyrakis (Trans Am Math Soc 348:2793–2810, 1996; 351:4183–4203, 1999), we identify the set of all maximal replicated subspaces. In particular, for any maximal replicated subspace we determine a positive basis of the subspace. Moreover we show that the union of all maximal replicated subspaces is the set of all marketed securities x ? X{x\in X} so that any option written on x is replicated. So we determine also the set of securities with replicated options.     

Cyprus small business ventures invigorate the economy

Cyprus has managed to advance itself and be recognized as one of the world's 32 advanced economies. By supporting local and foreign socioeconomic interests over the years, the small island‐nation today boasts rapid growth, full employment conditions, external and internal stability, strong telecommunications infrastructure, and a society well prepared to embrace the emerging knowledge economy. Recognizing its susceptibility to external economic trends as well as its attraction for various migrant groups, however, the people of Cyprus have embraced the benefits of putting their social capital to financial gain and the improvement of quality of life by supporting local business and welcoming foreign investment. © 2012 Wiley Periodicals, Inc.     

An overview of corporate social responsibility in Greece: perceptions,developments and barriers to overcome

The objective of this paper is to provide an overview of corporate social responsibility (CSR) in Greece and present the challenges that need to be met in order to further promote socially responsible business behaviour in the domestic economy. This is the first attempt to provide a systematic analysis of CSR in Greece and adds to the existing pool of knowledge of CSR embeddedness in countries where CSR awareness is still rather low, a literature field that is still quite limited. Drawing from prior literature, the paper is built around three basic questions in relation to the Greek context: how is CSR perceived by Greek business professionals? How is CSR practised in Greece? And which issues evident in the modern domestic environment act as underlying barriers to the broader dissemination of CSR in Greece? The extant empirical work suggests that, while CSR in Greece appears to be developing, there is still scope for improvement and further diffusion of relevant practices. While some of the patterns shaping CSR in Greece have been analysed, much work still remains to be carried out in extending and deepening our knowledge in this part of Europe.     

Aggregate returns to scale in Greek manufacturing

This paper takes an imperfect competition model of the economy in order to investigate for retuns to scale in Greek manufacturing and examines, through a small-scale macroeconomic model, the implication of estimates. For this purpose a price, wage and demand for output equations are estimated, using annual data for the period 1954–94. Prices come through the profits maximization process and depend on wage, capital rental, demand and a number of other variables denoing technology and market competition. Results are clearly in favour of increasing returns to scale hypothesis, although alternative explanations for the negative demand effect on prices cannot be excluded.