The Geometry and Topology of Twisted Quiver Varieties

Quivers have a rich history of being used to construct algebraic varieties via their representations in the category of vector spaces. It is also natural to consider quiver representations in a larger category, namely that of vector bundles on some complex variety equipped with a fixed locally free sheaf that twists the morphisms. For A-type quivers, such representations can be identified with the critical points of a Morse-Bott function on the moduli space of twisted Higgs bundles. Hence these ``twisted quiver varieties'' can be used to extract topological information about the Higgs bundle moduli space. We find a formula for the dimension of the moduli space of twisted representations of A-type quivers and geometric descriptions when each node of the quiver is represented by a line bundle. We then specialize to the so-called ``argyle quivers'', studied using Bradlow-Daskaloploulous stability parameters and pullback diagrams. Next we focus on the Riemann sphere P1 and obtain explicit expressions for the twisted quiver varieties as well as a stratification of these spaces via collisions of invariant zeroes of polynomials. We apply these results to some low-rank Higgs bundle moduli spaces. We then study representations of cyclic quivers, which can be viewed as corresponding to certain deformations of the Hitchin representations in non-abelian Hodge theory. When all of the ranks are 1, we describe the moduli spaces as subvarieties of the Hitchin system. We also draw out descriptions of the twisted quiver varieties for when the underlying curve is P1 and extend this to some other labellings of the quiver. We close with a discussion of possible applications of these ideas to hyperpolygon spaces as well as possible directions that use the motivic approach to moduli theory

Innovation by Experimenting in Public Services

Peer reviewe

A knowledge-based framework for service management

peer-reviewedThe purpose of this paper is to investigate how information and communication technologies are used for service standardisation, customisation, and modularisation by knowledge-intensive service firms through the development and empirical validation of a knowledge-based framework. This paper uses 59 in-depth interviews, observational data, and document analysis from case studies of three service-related departments in high-technology, multinational knowledge-intensive business services (KIBSs). Prior research does not conceptualise the relationships between service customisation, standardisation and modularisation. This paper seeks to overcome this gap by integrating insights from research on the role played by both knowledge and information and communication technologies (ICTs) to construct and validate a framework to deal with this gap. It outlines the implications for service firms' use of ICT to deal with increasing knowledge intensity as well as indicating the circumstances under which service knowledge is best customised, standardised and modularised. Further testing in other industries would prove useful in extending the usefulness and applicability of the findings. The originality of the paper lies in developing and validating the first framework to outline the relationship between how service knowledge is customised, standardised or modularised and indicating the associated issues and challenges. It emphasises the role of knowledge and technology. The value of this framework increases as more firms deal with increasing knowledge intensity in the services they provide and in their use of ICTs to reap the benefits of appropriate knowledge reuse.ACCEPTEDpeer-reviewe

Understanding How Social Entrepreneurs Fit into the Tourism Discourse

This chapter discusses how social entrepreneurs fit into the existing tourism discourse. It examines four areas of literature in particular, tourism entrepreneurs, sustainability, destination development and intrapreneurship, and analyzes how introducing the concept of social entrepreneurs into these discussions is useful, and contributes to our understanding. Furthermore the paper illustrates that as social entrepreneurs are relevant to a broad range of issues in the tourism literature this should prevent the development of research silos where social entrepreneurship scholars seek out their own vein of research. The nexus of common ground and interests, as displayed in this chapter, should enhance the development of research, thought and understanding of social entrepreneurs within the field as a whole The key argument is that research on social entrepreneurs is not just relevant for those interested in entrepreneurs it also effects our thinking on issues such as destination development, relationships between stakeholders, tourism policy and sustainability. The chapter concludes with a wide range of questions for further research

Effectiveness of regional innovation actions: cases from small, low-innovative regions

This paper attempts to identify the suitability of centrally designed innovation-related regional actions, examining the case of regions that started innovative activities from a low development level. Using the case of two Greek regions, the paper analyses the legacy left to the regional systems by a series of regional innovation programmes implemented during the 1990s and 2000s, whose main priorities were designed centrally without any regional consultation. The findings suggest that these programmes often provide the means for generating the first steps towards the creation of a Regional Innovation System; however often they create a dependency on publicly funded programmes

A dynamic theory of network failure

Organizational and sociological research dealing with network governance has mainly focused on network advantages rather than on their problems or dysfunctionalities. This left partially unexplored the field of network failure. Even if some early attempts at explicitly theorizing network failures have been made, we argue that explanations based mainly on social conditions (ignorance and opportunism) offered by this emerging theory (e.g. Schrank and Whitford, 2011), are not exhaustive. In this article we report the results of our empirical investigation on the underperforming network between the worldwide famous Venice Film Festival and its local hospitality system (in Venice, Italy). In the case study we are presenting, we will show how institutions have not been able to inhibit opportunism and sustain trust among network members because of mobilizing practices developed across formal lines of communication. With this work we propose a dynamic theory of network failure, answering to the more general call for network theories to focus the attention on agency and micro-processes

Entrepreneurship and Creative Professions – A Micro-Level Analysis

It has widely been recognized that creativity plays an immense role not only for arts, sciences, and technology, but also for entrepreneurship, innovation, and thus, economic growth. We analyze the level and the determinants of self-employment in creative professions at the level of individuals. The analysis is based on the representative micro data of the German Socio-Economic Panel (SOEP). The findings suggest that people in creative professions appear more likely to be self-employed and that a high regional share of people in the creative class increases an individual's likelihood of being an entrepreneur. Investigating the determinants of entrepreneurship within the creative class as compared to non-creative professions reveals only some few differences