A Characterization of Stochastically Stable Networks

Jackson and Watts [J. of Econ. Theory 71 (2002), 44-74] have examined the dynamic formation and stochastic evolution of networks. We provide a refinement of pairwise stability, p-pairwise stability, which allows us to characterize the stochastically stable networks without requiring the "tree construction" and the computation of resistance that may be quite complex. When a 1/2-pairwise stable network exists, it is unique and it coincides with the unique stochastically stable network. To solve the inexistence problem of p-pairwise stable networks, we define its set-valued extension with the notion of p-pairwise stable set. The 1/2-pairwise stable set exists and is unique. Any stochastically stable network is included in the 1/2-pairwise stable set. Thus, any network outside the 1/2-pairwise stable set must be considered as a nonrobust network. We also show that the 1/2-pairwise stable set can contain no pairwise stable network and we provide examples where a set of networks is more "stable" than a pairwise stable network.Network formation, Pairwise stability, Stochastic stability

A characterization of stochastically stable networks

Jackson and Watts [J. of Econ. Theory 71 (2002), 44-74] have examined the dynamic formation and stochastic evolution of networks. We provide a refinement of pairwise stability, p-pairwise stability, which allows us to characterize the stochastically stable networks without requiring the "tree construction" and the computation of resistance that may be quite complex. When a 1/2-pairwise stable network exists, it is unique and it coincides with the unique stochastically stable network. To solve the inexistence problem of p-pairwise stable networks, we define its set-valued extension with the notion of p-pairwise stable set. The 1/2-pairwise stable set exists and is unique. Any stochastically stable networks is included in the 1/2-pairwise stable set. Thus, any network outside the 1/2-pairwise stable set must be considered as a non-robust network. We also show that the 1/2-pairwise stable set can contain no pairwise stable network and we provide examples where a set of networks is more "stable" than a pairwise stable network

An introduction to spectral distances in networks (extended version)

Many functions have been recently defined to assess the similarity among networks as tools for quantitative comparison. They stem from very different frameworks - and they are tuned for dealing with different situations. Here we show an overview of the spectral distances, highlighting their behavior in some basic cases of static and dynamic synthetic and real networks

The Pigouvian Tax Rule in the Presence of an Eco-Industry

Pollution abatement goods and services are now largely being delivered by a specialized “eco-industry.” This note reconsiders Pigouvian taxes in this context. We find that the optimal emission tax will depart from the marginal social cost of pollution according to the polluters’ and the environment firms’ relative market power.Pigouvian taxes, Environment industry

Tinbergen and Theil Meet Nash: Controllability in Policy Games

This paper generalizes the classical theory of economic policy to a static LQ-strategic context between n players. We show how this generalized version of controllability can profitably be used to deal with policy ineffectiveness issues and Nash equilibrium existence.Policy games, policy ineffectiveness, static controllability, Nash equilibrium existence

Network Capital and Social Trust: Pre-Conditions for ‘Good’ Diversity?

This paper unpicks the assumption that because social networks underpin social capital, they directly create it – more of one inevitably making more of the other. If it were that simple, the sheer quantity of networks criss-crossing a defined urban space would be a proxy measure for the local stock of social capital. Of course the interrelationships are more complex. Two kinds of complication stand out. The first is specific: networks have both quantitative and qualitative dimensions, but the two elements have no necessary bearing on each other. The shape and extent of a network says nothing about the content of the links between its nodes. Certainly the line we draw between any two of them indicates contact and potential connection, but what kind of contact, how often, how trusting, in what circumstances, to what end…? Reliable answers to these questions need more than surface maps or bird’s eye accounts of who goes where, who speaks to whom. The second complication is a general, not to say universal, difficulty. We are stuck with the fact that sociological concepts - networks, social capital and trust included - are ‘only’ abstractions. They are ways of thinking about the apparent chaos of people behaving all over the place – here, to make it worse, in multi-cultural urban environments - but none of them is visible to be measured, weighed or quantified. This does not make the concepts ‘untrue’, and it should not stop them being useful. My hope is that we can find a nuanced perspective which will at least make the complications intelligible. At best, a multi-layered model will account for diversity in the nature of trust; and for variations in the way social capital is hoarded or distributed within and across ethnic boundaries. It would be contribution enough if we were able to specify the conditions which cause social capital, as Puttnam formulates it, to be exclusionary or inclusionary in its effect.Network capital, Social trust, ‘Good’ diversity

A Data Envelopment Analysis Approach to the Assessment of Natural Parks’ Economic Efficiency and Sustainability. The Case of Italian National Parks

Wilderness protection is a growing necessity for modern societies, and this is particularly true for areas where population density is extremely high, as for example Europe. Conservation, however, implies very high opportunity costs. It is thus crucial to create incentives to efficient management practices, to promote benchmarking and to improve conservation management. In the present paper we propose a methodology based on Data Envelopment Analysis, DEA, a non parametric benchmarking technique specifically developed to assess the relative efficiency of decision-making units. In particular, the objective of the discussed methodology is to assess the relative efficiency of the management units of the protected area and to indicate how it could be improved, by providing a set of guidelines. The main advantage of this methodology is that it allows to assess the efficiency of natural parks’ management not only internally (comparing the performance of the park to itself in time) but also by external benchmarking, thus providing new and different perspectives on potential improvements. Although the proposed methodology is fairly general, we have applied it to the context of Italian National Parks in order to produce a representative case study. Specifically, the choice of adequate cost and benefit indicators is a very important and delicate phase of any benchmark analysis. For this purpose, a questionnaire was used to investigate the opinions of Italian National Parks managers and stakeholders and to define the relevant indicators for the analysis. Finally, relevant policy implications for the case study are given.Data envelopment analysis, Natural park management

Value Through Diversity: Microfinance and Islamic Finance and Global Banking

Internet resources, extended media coverage and international organizations’ reports recently witness the increasing interest of western banks in new models of finance, particularly Islamic finance and microfinance. This new trend is not only channeled through the frame of corporate social responsibilities programs and policies or limited to ad hoc financial institutions (like microcredit banks or Islamic banks) as it is entering the financial offer of mainstream banks. The paper primarily outlines that many elements of microfinance could be considered consistent with the broader goals of Islamic banking. Apart from pure economic considerations which are not the aim of this analysis, the paper supports the thesis that by addressing new markets and embracing unconventional financial proposals, the global banking sector can contribute to the quest for diversity-oriented policies posed by an increasingly globalised scenario. The consequences this new trend is likely to have on inner banking structures are still unknown and are likely to interest the issue of wealth distribution. Moreover, from a more general point of view, by showing that even different moral ethos deep rooted in different cultural paradigms can be as profitable and available as western capitalistic ones, the banking sector can play a potential role in disseminating awareness on specific cultural and religious issues, resulting in increased integration of Muslim communities and low income investors in the long run and supporting commercial banks the close relation between economy and culture.Microfinance, Islamic finance, Diversity, Multiculturalism, Global banking

Modeling ‘No-choice’ Responses in Attribute Based Valuation Surveys

We examine the impact of providing a ‘no-choice’ option in an attribute based valuation experiment. The aim of the experiment was to assess monetary values of cockle fishery management practices in the Dutch Wadden Sea for different stakeholder groups, namely Dutch citizens, local residents, and tourists. The current policy debate about the management of the Wadden Sea stresses the fact that individual preferences with respect to cockle-fishery differ. The aim of this paper is to analyze the individual preferences in an objective way. Special attention is given to the influence of including a ‘no-choice option’, which is analyzed using a nested logit model. We test whether the full set of policy options can be considered as close substitutes. The estimation results show that the influence of including the no choice option differs among the stakeholders considered.Stakeholder valuation, Stated choice method, Multinomial logit model, Binary logit model

An Open Source Based Data Warehouse Architecture to Support Decision Making in the Tourism Sector

In this paper an alternative Tourism oriented Data Warehousing architecture is proposed which makes use of the most recent free and open source technologies like Java, Postgresql and XML. Such architecture's aim will be to support the decision making process and giving an integrated view of the whole Tourism reality in an established context (local, regional, national, etc.) without requesting big investments for getting the necessary software.Tourism, Data warehousing architecture