30 years into the existence of a unified German Republic, the emphasis of differences, the use of stereotypes and the existence of economic inequalities remain. This affects the younger post-unification generation - children that were born after 1989. The study is concerned with the investigation into the process of identity construction along the East-West binary and the effects this process has on said binary division. Thereby, the Eastern German perspective is stressed by using in-depth interviews with Eastern German respondents for a narrative analysis that is based on structural, interactional and performative principles. This thesis sees its contribution in the renewal of the deadlocked debate about the German East-West discourse by taking a postmodern stance on identity while applying a sociological theoretical framework and postcolonial concepts. The ambivalence in identity construction and the indication for a hybrid form of identity point at the existence of a Third Space, in which socio-political transformations can take place.

The doctoral thesis is focused on the purpose use of existing symbol sets of national map series to create a new harmonized set and to effective use of existing symbols of large scale maps. The theoretical part deals with the development of the theoretical concept of cartographic language, possibilities of cartographic interpretation and procedures for creating symbol sets. This part also provides an overview of national and international organizations and a summary of legislation, which are related to cartographic production and which seek to facilitate sharing and transfering of data among states. Furthermore, this thesis evaluates the current possibilities of purpose use of symbol sets with emphasis on converging cartographic outputs within the Czech Republic and the European Union. The main aim of the thesis is to design a new symbol key, which will be used by the Land Survey Office to distribute a new edition of national map series. The development of new symbols follows the comparison of cartographic interpretation on maps published by national organizations in the Czech Republic and selected countries of the European Union. Simultaneously the whole national map series is undergoing fundamental innovations. This is also described in the thesis. This part of the thesis was created in closed cooperation with the Land Survey Office in Prague and with the support of the Military Geographical and Hydrometeorological Office of General Josef Churavý in Dobruška. The comprehensive symbol set of the new Base Topographic Maps of the Czech Republic at a scale of 1:5 000, 1:10 000, 1:25 000, 1:50 000, 1:100 000 and 1:250 000 is the main result of this thesis. There is designed solution for more effective use of existing symbols in the form of a purpose-built database of symbols for the creation of large scale maps in conclusion of this thesis.

Sustainability is a universal topic that has gained in significance during the last decade due to the increased risks for society as well as the environment itself. Therefore, a lot more attention is given to how companies disclose upon their impact on environment, society and governance. This paper aims to pick up on criticism to sustainability reporting regarding the variety of different frameworks surrounding this topic and investigate upon how companies use them to create their reports and if, in their opinion, unification can be reached in the nearby future. The second objective of this thesis is to explore upon and collect knowledge regarding the developing role of the new profession of the ESG/Sustainability controller. To reach the research objectives and collect sufficient data, semi-structured, qualitative interviews have been conducted with six companies and their respective sustainability reporting responsible. Previous research points out that the ‘arena’ of sustainability reporting frameworks has become too dense. This has led to companies firstly struggling to navigate through the enormous amount of regulations and guidelines, secondly adversely affected the implementation of harmonization within sustainability reporting and thirdly using their reports as marketing tools. These theoretical findings have been mostly supported by the results of this thesis. Almost all of the interviewed companies have adopted a common index, called GRI, that builds their sustainability disclosure base. However, the findings of this thesis point out that their efforts, to go beyond this reporting guideline, can be connected to motives that are either of external, operational, transparency or recruitment nature. Even though companies would wish for a common, unified reporting framework, such as the upcoming inclusion of CSRD in the future, and see potential advantages, there are some specific, current challenges that have to be overcome first regarding sustainability reporting. Nevertheless, from the data analyzed it is evident that companies are looking forward to this new, mandatory reporting regulation and prepare themselves adequately and intensively. The results of the qualitative study regarding the development of the new controller profession further suggests that the ESG/Sustainability controller has a broad post-graduate background, however, not only in business administration. One reason is that the tasks of this new profession vary by quite some margin from traditional controlling tasks and their responsibilities also go beyond merely preparing, analyzing financial reports and supporting management, but are dedicated to the sustainability reporting process and other sustainability projects.

Unification of concept terms is a new kind of inference problem for Description Logics, which extends the equivalence problem by allowing to replace certain concept names by concept terms before testing for equivalence. We show that this inference problem is of interest for applications, and present first decidability and complexity results for a small concept description language. / This revised version of LTCS-Report 97-02 provides a stronger complexity result in Section 6. An abridged version will appear in Proc. ECAI'98 .

Unification modulo the theory of Boolean algebras has been investigated by several autors. Nevertheless, the exact complexity of the decision problem for unification with constants and general unification was not known. In this research note, we show that the decision problem is complete for unification with constants and PSPACE-complete for general unification. In contrast, the decision problem for elementary unification (where the terms to be unified contain only symbols of the signature of Boolean algebras) is 'only' NP-complete.

Unification of concept terms is a new kind of inference problem for Description Logics, which extends the equivalence problem by allowing to replace certain concept names by concept terms before testing for equivalence. We show that this inference problem is of interest for applications, and present first decidability and complexity results for a small concept description language.

The paper contains a proof of completeness of a goal-directed inference system for general E-unification with eager Variable Elimination. The proof is based on an analysis of a concept of ground, equational proof. The theory of equational proofs is developed in the first part. Solving variables in a goal is then shown to be reflected in defined transformations of an equational proof. The termination of these transformations proves termination of inferences with eager Variable Elimination.

The Description Logic EL is an inexpressive knowledge representation language, which nevertheless has recently drawn considerable attention in the knowledge representation and the ontology community since, on the one hand, important inference problems such as the subsumption problem are polynomial. On the other hand, EL is used to define large biomedical ontologies. Unification in Description Logics has been proposed as a novel inference service that can, for example, be used to detect redundancies in ontologies. In a recent paper, we have shown that unification in EL is NP-complete, and thus of a complexity that is considerably lower than in other Description Logics of comparably restricted expressive power. In this paper, we introduce a new NP-algorithm for solving unification problem in EL, which is based on a reduction to satisfiability in propositional logic (SAT). The advantage of this new algorithm is, on the one hand, that it allows us to employ highly optimized state of the art SAT solverswhen implementing an EL-unification algorithm. On the other hand, this reduction provides us with a proof of the fact that EL-unification is in NP that is much simpler than the one given in our previous paper on EL-unification.

Unification in Description Logics has been proposed as a novel inference service that can, for example, be used to detect redundancies in ontologies. The inexpressive Description Logic EL is of particular interest in this context since, on the one hand, several large biomedical ontologies are defined using EL. On the other hand, unification in EL has recently been shown to be NP-complete, and thus of considerably lower complexity than unification in other DLs of similarly restricted expressive power. However, EL allows the use of the top concept (>), which represents the whole interpretation domain, whereas the large medical ontology SNOMEDCT makes no use of this feature. Surprisingly, removing the top concept from EL makes the unification problem considerably harder. More precisely, we will show that unification in EL without the top concept is PSpace-complete. / This is an updated version of the original report that includes Appendix A on locality of unifiers.

Unification has been investigated both in modal logics and in description logics, albeit with different motivations. In description logics, unification can be used to detect redundancies in ontologies. In this context, it is not sufficient to decide unifiability, one must also compute appropriate unifiers and present them to the user. For the description logic EL, which is used to define several large biomedical ontologies, deciding unifiability is an NP-complete problem. It is known that every solvable EL-unification problem has a minimal unifier, and that every minimal unifier is a local unifier. Existing unification algorithms for EL compute all minimal unifiers, but additionally (all or some) non-minimal local unifiers. Computing only the minimal unifiers would be better since there are considerably less minimal unifiers than local ones, and their size is usually also quite small. In this paper we investigate the question whether the known algorithms for EL-unification can be modified such that they compute exactly the minimal unifiers without changing the complexity and the basic nature of the algorithms. Basically, the answer we give to this question is negative.