Admissible subcategories of noncommutative curves

We study admissible subcategories of the derived categories of smooth noncommutative curves as classified by Reiten-van den Bergh. We prove phantom subcategories do not exist in these derived categories and we obtain a complete classification of the admissible subcategories of the bounded derived category of representations of an acyclic quiver.Comment: 8 pages, results expande

Contract Types, Institutional Distance and Operational Performance: Evidence from Global Trade Flows in the LNG Industry

Supporting Information is available online at https://onlinelibrary.wiley.com/doi/full/10.1111/1467-8551.12672#support-information-section .We would like to express our gratitude to Kpler for granting us access to its database in order to process their data and conduct this research study. The views in this paper are solely the responsibility of the authors and should not be interpreted as reflecting the views of their institutions and organizations. [Correction added on 7th of November 2022, after first online publication: Figure 1 and hypotheses numbers have been updated in this version.].Copyright © 2022 The Authors. In this study, we examine the relationship between contract types, institutional distance and operational performance in the context of cross-border trade in the liquefied natural gas (LNG) industry. Drawing on the buyer–supplier long-term relationships literature, we argue for a negative link between short-term contractual agreements and operational performance. Further, drawing insights from institutional theory, we contend that a high level of formal and informal institutional distance between the origin (i.e. supplier) and destination (i.e. buyer) countries reduces operational performance. We also argue that formal and informal institutional distance mitigates the negative effect of short-term contracts on operational performance. Finally, we draw on the role of ‘asymmetry in distance’ by examining the direct and moderating effect of both the relevance and direction of formal institutional distance. We test our assumptions using LNG global trade flows from 39 source countries to 44 destination countries over the 2008–2017 period (a total of 17,447 shipments). Our study extends our knowledge on the operational performance implications of buyer–supplier relationships and stresses the important role formal and informal institutional distance plays as a direct and moderating effect on this relationship

Extending the Decision-Making Capabilities in Remanufacturing Service Contracts by Using Symbiotic Simulation

Remanufacturing is a critical enabler of a resource efficient manufacturing industry that has long been associated with high value products. Over time, the commercial relationship between customers and service providers has been made through the fulfilment of rights and obligations under remanufacturing service contracts. Nonetheless, financial analysis to evaluate the contract terms and conditions are becoming increasingly difficult to conduct due to complex decision problems inherent in remanufacturing systems. In order to achieve better and safer decision-making to shape the business strategies, remanufacturers often employ computer-based simulation tools to assess contractual obligations and customers’ needs. This paper discusses the roles of a symbiotic simulation system (SSS) in supporting decision-making in remanufacturing systems. An industrial case study of power transformer remanufacturing illustrates how SSS can support contract remanufacturers in managing service contracts planning and execution. By linking the simulation model to the physical system, it has been demonstrated that the capabilities of the remanufacturers to make critical decisions throughout the entire service contract period can be extended

Metrics for optimising the multi-dimensional value of resources recovered from waste in a circular economy: A critical review

© 2017 The Authors - Established assessment methods focusing on resource recovery from waste within a circular economy context consider few or even a single domain/s of value, i.e. environmental, economic, social and technical domains. This partial approach often delivers misleading messages for policy- and decision-makers. It fails to accurately represent systems complexity, and obscures impacts, trade-offs and problem shifting that resource recovery processes or systems intended to promote circular economy may cause. Here, we challenge such partial approaches by critically reviewing the existing suite of environmental, economic, social and technical metrics that have been regularly observed and used in waste management and resource recovery systems' assessment studies, upstream and downstream of the point where waste is generated. We assess the potential of those metrics to evaluate ‘complex value’ of materials, components and products, i.e., the holistic sum of their environmental, economic, social and technical benefits and impacts across the system. Findings suggest that the way resource recovery systems are assessed and evaluated require simplicity, yet must retain a suitable minimum level of detail across all domains of value, which is pivotal for enabling sound decision-making processes. Criteria for defining a suitable set of metrics for assessing resource recovery from waste require them to be simple, transparent and easy to measure, and be both system- and stakeholder-specific. Future developments must focus on providing a framework for the selection of metrics that accurately describe (or at least reliably proxy for) benefits and impacts across all domains of value, enabling effective and transparent analysis of resource recovery form waste in circular economy systems.We gratefully acknowledge support of the UK Natural Environ-ment Research Council (NERC) and the UK Economic and SocialResearch Council (ESRC) who funded this work in the context of‘Complex Value Optimisation for Resource Recovery’(CVORR)project (Grant No. NE/L014149/1)

Limits of stability conditions and their geometry

171 pagesAfter giving a brief survey of the study of derived categories in algebraic geometry, I present a pair of research papers. The first, joint with Daniel Halpern-Leistner and Jeffrey Jiang, introduces the notion of quasi-convergent paths in the space of stability conditions. We prove that quasi-convergent paths give rise to decompositions of triangulated categories (e.g. derived categories of coherent sheaves on a variety) and that conversely for a smooth and proper dg-category all polarized semiorthogonal decompositions arise in this fashion. In the second paper, I study the geometry of certain moduli spaces of genus 0 curves with differentials called multiscale lines which were introduced in joint work with Daniel Halpern-Leistner. I prove that these spaces are complex projective varieties by giving an explicit isomorphism with a blow-up of a linear subspace arrangement of projective space. I use this isomorphism to connect these spaces of multiscale lines with other spaces in the literature studied by Zahariuc