Duality theory for robust utility maximisation

In this paper, we present a duality theory for the robust utility maximisation problem in continuous time for utility functions defined on the positive real line. Our results are inspired by – and can be seen as the robust analogues of – the seminal work of Kramkov and Schachermayer (Ann. Appl. Probab. 9:904–950, 1999). Namely, we show that if the set of attainable trading outcomes and the set of pricing measures satisfy a bipolar relation, then the utility maximisation problem is in duality with a conjugate problem. We further discuss the existence of optimal trading strategies. In particular, our general results include the case of logarithmic and power utility, and they apply to drift and volatility uncertainty.

     

“I will survive”: Online streaming and the chart survival of music tracks

Digital streaming has had a profound effect on the commercial music sector and now accounts for 80% of industry revenues in the United States. This study investigates the consumption of music on digital streaming platforms by analyzing the factors affecting the chart survival of individual music tracks. Our data are taken from the Spotify Global Top 200 between January 2017 and January 2020, containing observations on 3,007 unique tracks by 642 artists over 1,087 days. We identify a number of unique consumption traits applicable to online streaming services, which we use to explain variations in chart longevity. We find a positive association between the amount of time a track spends in the chart and the involvement of a major label. We also find that the level of competition from other chart entries, as well as some elements related to the pattern of diffusion, associates significantly with the likelihood of chart survival. The study highlights several important managerial implications for key industry stakeholders.     

From private label to co-branded credit card: an assessment of the impact of a change in value proposition over customer value perception and company value capture

Journal of Financial Services Marketing - Purpose: The aim of this paper is to evaluate the success of a value proposition over time, considering two aspects: customer’s perceived value and...     

Do the COVID-19 Crisis,Ageing and Climate Change Put Swiss Fiscal Sustainability at Risk?

The ongoing coronavirus pandemic crisis as well as demographic and climate change pose major challenges for public finances. This article deals with the implications of demographic trends in Switzerland, i.e. the progressive ageing of the population and its impact on the country’s public finances in the long run. As the analysis shows, the brunt of the demographic burden is borne by the old-age pension scheme, health and long-term care. This article also addresses the financial ramifications of the COVID-19 crisis and shows the need for economic policy action over the longer term to ensure the sustainability of public finances in Switzerland. Furthermore, a qualitative assessment of climate change is included, as it constitutes an additional major long-term challenge for public finances.

     

From Greenwashing to Machinewashing: A Model and Future Directions Derived from Reasoning by Analogy

Journal of Business Ethics - This article proposes a conceptual mapping to outline salient properties and relations that allow for a knowledge transfer from the well-established greenwashing...     

The Cost of War: A Comment and a Reply

Intereconomics - In the July/August issue of Intereconomics, Ilona Sologoub argued that increasing the cost of war would limit the ability of an authoritarian state to wage a war. Here, Charles D....     

Khat-chewing in liminal leisure spaces: British-Somali youth on the margins

Khat-chewing, a controversial leisure activity within the Somali diaspora in Britain, has received little attention within the academic field of Leisure Studies. This paper reports on ethnographic research to provide insights into the unique locations where young British-Somali men chew khat, exposing the liminal qualities of such localities. The paper begins with an overview of the contentious position khat-chewing occupies within Somali communities in Britain, highlighting reasons why young British-Somali men hide their association with the leisure practice. The discussion that follows considers how young male khat users conceptualise spatial environments, exposing how these locations temporarily produce a dual sense of privacy and sociality. The ambiences of such temporary leisure spaces remain open to the prospect of discovery, resulting in the use of discretionary tactics to maintain a sense of secrecy. In this context, we discuss how khat-chewing offers a sense of cultural identity and belongingness while also marking young British-Somali men as outsiders – even within their own communities.     

Family firm’s management composition: the role played by family members’ age in TMT and supervisor levels

Quality & Quantity - Family firms (FFs) are the backbone of entrepreneurial fabric in many countries. Management of such businesses is complex because of their features: the overlap between...     

Age as double‐edged sword among victims of customer mistreatment: A self‐esteem threat perspective

Service workers are expected to maintain high‐quality service delivery despite customer mistreatment—the poor‐quality treatment of service workers by customers—which can be demeaning and threatening to self‐esteem. Although service work is increasingly delivered by middle‐aged and older workers, very little is known about how employees across the age range navigate abuse from customers on the job. Does advancing age help or hinder service performance in reaction to customer mistreatment? Drawing on strength and vulnerability integration theory, we proposed that age paradoxically both helps and hinders performance after customer mistreatment, albeit at different stages. We tested our proposed model in a two‐sample field investigation of service workers and their supervisors using a time‐lagged, dyadic design. Results showed that age heightens the experience of self‐esteem threat but, nevertheless, dampens reactions to self‐esteem threat, leading to divergent effects on performance at different stages. Implications for age and service work, as well as aging and the sense of self, are discussed.     

Multi-level and mixed-level <Emphasis Type="Italic">k</Emphasis>-circulant supersaturated designs

Supersaturated designs (SSDs) constitute an important class of fractional factorial designs that could be extremely useful in factor screening experiments. Most of the existing studies have focused on balanced designs. This paper provides a new lower bound for the \(E(f_{NOD})\)-optimality measure of SSDs with general run sizes. This bound is a generalization of existing bounds since it is applicable to both balanced and unbalanced designs. Optimal multi and mixed-level, balanced and nearly balanced SSDs are constructed by applying a k-circulant type methodology. Necessary and sufficient conditions are introduced for the generator vectors, in order to pre-ensure the optimality of the constructed k-circulant SSDs. The provided lower bounds were used to measure the efficiency of the generated designs. The presented methodology leads to a number of new families of improved SSDs, providing tools for directly constructing optimal or nearly-optimal k-circulant designs by just checking the corresponding generator vector.