Pivotal tricategories and a categorification of inner-product modules

This article investigates duals for bimodule categories over finite tensor categories. We show that finite bimodule categories form a tricategory and discuss the dualities in this tricategory using inner homs. We consider inner-product bimodule categories over pivotal tensor categories with additional structure on the inner homs. Inner-product module categories are related to Frobenius algebras and lead to the notion of $*$-Morita equivalence for pivotal tensor categories. We show that inner-product bimodule categories form a tricategory with two duality operations and an additional pivotal structure. This is work is motivated by defects in topological field theories.Comment: 64 pages, comments are welcom

Emission Trading Systems and the Optimal Technology Mix

Cap and trade mechanisms enjoy increasing importance in environmental legislation worldwide. The most prominent example is probably given by the European Union Emission Trading System (EU ETS) designed to limit emissions of greenhouse gases, several other countries already have or are planning the introduction of such systems. One of the important aspects of designing cap and trade mechanisms is the possibility of competition authorities to grant emission permits for free. Free allocation of permits which is based on past output or past emissions can lead to inefficient production decisions of firms’ (compare for example B¨ohringer and Lange (2005), Rosendahl (2007), Mackenzie et al. (2008), Harstad and Eskeland (2010)). Current cap and trade systems grant free allocations based on installed production facilities, which lead to a distortion of firms’ investment incentives, however. It is the purpose of the present article to study the impact of a cap and trade mechanism on firms’ investment and production decisions and to analyze the optimal design of emission trading systems in such an environment

Multi-Dimensional Inheritance

In this paper, we present an alternative approach to multiple inheritance for typed feature structures. In our approach, a feature structure can be associated with several types coming from different hierarchies (dimensions). In case of multiple inheritance, a type has supertypes from different hierarchies. We contrast this approach with approaches based on a single type hierarchy where a feature structure has only one unique most general type, and multiple inheritance involves computation of greatest lower bounds in the hierarchy. The proposed approach supports current linguistic analyses in constraint-based formalisms like HPSG, inheritance in the lexicon, and knowledge representation for NLP systems. Finally, we show that multi-dimensional inheritance hierarchies can be compiled into a Prolog term representation, which allows to compute the conjunction of two types efficiently by Prolog term unification.Comment: 9 pages, styles: a4,figfont,eepic,eps

A holistic framework for the analysis of landscape changes following organic farming

In this paper I reflect on the design of an appropriate methodological framework for my Ph.D.-project. Holism is widely recognised a vital concept for research on human-environment relationships. This is especially the case when agriculture’s impact on land-scapes is studied. Thus, for my study on landscape changes following conversion to or-ganic farming, I discuss holism in terms of its relevance in principal and in terms of its actual practicability. I recognise that a holistic angle is decisive in order to analyse and understand the spatial and temporal dynamics of the landscape and the multitude forces and processes that have a bearing on them. Keeping a general holistic concept in mind can elucidate factors and processes that might be overlooked in a purely reductionistic ap-proach and a holistic concept can thus prevent from drawing inadequate and premature conclusions. Additionally, in order to explain spatial and temporal dynamics in the physi-cal landscape, I discuss the integration of quantitative and qualitative methods. Quantita-tive data can point to statistical tendencies and relations. However, the underlying causes and processes, especially when these concern human activities and decision taking, can only be detected with qualitative information. Based on these considerations I suggest a holistic framework for my study where quantitative and qualitative methods in a com-plementary sense can contribute to a to a profound description and understanding of landscape changes following conversion to organic farming