Una nuova caratterizzatione dell'ammissibilità nella teoria delle decisioni

In questo lavoro viene fornita una nuova caratterizzazione dell'ammissibilità attraverso un adeguato uso della nozione di ammissibilità parziale. Questa caratterizzazione consente di affrontare le questioni riguardanti la completezza della classe delle decisioni ammissibiliti sotto condizioni «maneggevoli». Fornisce inoltre un approccio unificante al problema della completezza che consente di derivare, come casi particolari, alcuni risultati già noti nella letteratura sull'argomento.

---

In this paper a new characterization of admissibility is given for general decision problems. It is based on an adequate use of the notion of partial admissibility.A general decision problem is usually synthetized by a triplet (, , ) where is the states (or parameters) space, the set of available decisions and is a family of real valued functions defined on and expressing numerically the consequences of choosing when the state is . The set is regarded as a subset of the space of all real valued functions on endowed with the topology of pointwise convergence.As for as admissibility is concerned all the pertinent information about decisions are contained in the corresponding functionsW .This allows to introduce a notion of partial admissibility through the neigh-bourhoods of this topology. Admissibile decisions are then shown to be limits of monotone non increasing sequences of partially admissible decisions.Moreover this topological characterization allows to prove the completeness of classes of admissible decisions under acceptable systems of conditions which contain as special cases, known results in literature.

---

---

Lavoro svolto nell'ambito del Gruppo Nazionale per l'Analisi Funzionale e le sue Applicazioni del C.N.R.     

La quasi-ammissibilitá nella teoria generale delle decisioni

In questo lavoro, la nozione di quasi-ammissibilità, come ampliamento della nozione di ammissibilità, viene formalizzata esplicitando una topologia sullo spazio funzionale in cui sono immerse le funzioni di perdita corrispondenti alla classe di decisioni del problema. Per questa via è possibile analizzare il concetto di quasi-ammissibilità senza restrizioni sullo spazio degli stati di natura. Si verifica poi, che le nozioni già note di ε-ammissibilità costituiscono casi particolari del-l’impostazione più generale qui proposta.

---

It is known that in Decision Theory under Uncertainty the notion of admissibility and almost-admissibility plays an important role since it does not depend properly on the chosen optimality criterion. The main goal of the known notions of ε-admissibility is to conveniently enlarge the class of the admissible decision rules, which for some problems can be empty. Once observed that the notion of ε-equivalence between two decision rules is based on the fact that the decision are “close” each other, it is then natural to study the notion of ε-equivalence in a topological context. Here the functional space of the loss functions associated to the class of the decision rules is equipped with the product topology which the functional space is naturally endoved of. It this framework it is possible to study the notion of almost-admissibility independently of the characteristics of the states space. The known definitions of ε-admissibility are then reduced to particular cases of this more general approach.

---

---

Lavoro eseguito nell’ambito del Gruppo Nazionale per l’Analisi Funzionale e le sue Applicazioni del C.N.R.     

Grand challenges and entrepreneurship: Emerging issues,research streams,and theoretical landscape

This study discusses how the role of entrepreneurship in addressing the so-called “grand challenges” (e.g., poverty, inequality, pollution, climate change) is evolving and could further evolve, based on the ongoing conversation in the scholarly community. To develop the discussion, we conducted the following steps: (1) a computer-aided semantic analysis; (2) an analysis of the evolution of literature streams; and (3) a network analysis of advocated theories and approaches. All three analyses were based on a selection of 358 publications retrieved via a keyword search and 27 further publications retrieved via an analysis of five recent and relevant special issues published by important scientific journals. Our results show that the call to address grand challenges, particularly after the publication of the United Nations’ Sustainable Development Goals (SDGs), is radically transforming entrepreneurship research, with new issues emerging and replacing traditional issues as core to the discipline, marking a rapid and complex dynamics of research stream divergence and convergence. Similarly, the network of theories and approaches advocated by recent agenda-setting articles depicts an emerging theoretical landscape that is highly innovative. This new theoretical landscape revolves around systems thinking and Ostrom’s theory of the commons as the two key poles, with the embeddedness, stakeholder, institutional, effectuation, processual, and design-oriented approaches being the cross-fertilizing forces linking these two poles. In the final section, we present the nine articles included in the special issue titled “Grand Challenges and Entrepreneurship: Emerging Issues and Research Streams” and briefly synthesize these in the light of the ongoing evolution of the literature.

     

Contractual networks: an organizational model to reduce the competitive disadvantage of small and medium enterprises (SMEs) in Europe’s less developed regions. A survey in southern Italy

International Entrepreneurship and Management Journal - Limitations faced by southern Italy’s small enterprises due to their dimensions may be overcome by cooperation strategies and network...     

Trade‐offs in the performance of alternative farming systems

Numerous alternative farming systems are proposed as solutions to the sustainability challenges of today's conventional farming systems. In this paper, we review the production, environmental, and socioeconomic performance of three widely discussed and promoted alternative farming systems—organic, smallholder, and urban agriculture. We show that both organic and smallholder agricultures have some benefits, but also entail important trade‐offs; organic has environmental benefits, and also livelihood, health, and nutritional benefits for producers and consumers, but is hampered by lower yields and higher prices. Smaller farms have higher yields and host higher biodiversity, but are hampered by lower incomes to farmers. Urban agriculture can take some pressure off rural landscapes, provide nutritional benefits to the urban poor, and engage urban dwellers in addressing food system challenges, but it simply cannot scale up to be a substantial solution in and of itself. We suggest that instead of focusing on alternative systems, we should identify pathways to sustainable farming for all systems, reforming conventional systems where they perform poorly, and transitioning to alternative systems in contexts where they perform best.     

Organizing for Commons-Enabling Decision-Making Under Conflicting Institutional Logics in Social Entrepreneurship

Social entrepreneurship develops innovative opportunities and solutions aimed to (re)generate the common good. This emerging organizational form poses unprecedented challenges to group decision and negotiation studies. This article leverages conceptual tools from the literature on the commons and institutional logics as it explores the organizational conditions of social entrepreneurship that trigger commons-enabling decision-making in its organizational field. Through an inductive analysis of a longitudinal case, this study proposes a model that highlights the critical role of the bridging organization that can be introduced by the social entrepreneur in a previously fragmented organizational field. This bridging organization is in the condition to develop an innovative co-creation logic that can serve as a common ground to enable collaboration between actors from diverse and even conflicting institutional logics. The proposed model suggests that a practice-driven path to the construction of such a common ground for decision-making is more effective than a disclosure-driven path, which is based on classical conflict analysis techniques. The ICT-enabled activity system developed by the social entrepreneur injects transparency and traceability into a previously opaque field, thus creating the conditions for distributed, flexible, and complementary sense- and decision-making processes that develop and protect the commons.