Conditionals are omnipresent, in everyday life as well as in scientific environments; they represent generic knowledge acquired inductively or learned from books. They tie a flexible and highly interrelated network of connections along which reasoning is possible and which can be applied to different situations. Therefore, conditionals are important, but also quite problematic objects in knowledge representation. This book presents a new approach to conditionals which captures their dynamic, non-proportional nature particularly well by considering conditionals as agents shifting possible worlds in order to establish relationships and beliefs. This understanding of conditionals yields a rich theory which makes complex interactions between conditionals transparent and operational. Moreover,it provides a unifying and enhanced framework for knowledge representation, nonmonotonic reasoning, belief revision,and even for knowledge discovery.

This book covers lymphoproliferative disorders in patients with congenital or acquired immunodeficiencies. Acquired immunodeficiencies are caused by infections with the human immunodeficiency virus or arise following immunosuppressive therapy administered after organ transplantation or to treat connective tissue diseases such as rheumatoid arthritis. It was recently discovered that various diseases or therapeutic modalities that induce a state of immunosuppression may cause virally driven lymphoproliferations. This book summarizes for the first time this group of immunodeficiency-associated lymphoproliferations.

This volume contains the papers presented at the “Second International S- posium on Foundations of Information and Knowledge Systems” (FoIKS 2002), which was held in Schloß Salzau, Germany from February 20th to 23rd, 2002. FoIKS is a biennial event focusing on theoretical foundations of information and knowledge systems. It aims to bring together researchers working on the theoretical foundations of information and knowledge systems and to attract researchers working in mathematical ?elds such as discrete mathematics, c- binatorics, logics, and ?nite model theory who are interested in applying their theories to research on database and knowledge base theory. FoIKS took up the tradition of the conference series “Mathematical Fundamentals of Database S- tems” (MFDBS) which enabled East-West collaboration in the ?eld of database theory. The ?rst FoIKS symposium was held in Burg, Spreewald (Germany) in 2000. Former MFDBS conferences were held in Dresden (Germany) in 1987, Visegr ́ ad (Hungary) in 1989, and in Rostock (Germany) in 1991. Proceedings of these previous events were published by Springer-Verlag as volumes 305, 364, 495, and 1762 of the LNCS series. In addition the FoIKS symposium is intended to be a forum for intensive d- cussions. For this reason the time slot of long and short contributions is 60 and 30 minutes respectively, followed by 30 and 15 minutes for discussions, respectively. Furthermore, participants are asked in advance to prepare as correspondents to a contribution of another author. There are also special sessions for the pres- tation and discussion of open research problems.

Ten years of ,,Fuzzy Days“ in Dortmund! What started as a relatively small workshop in 1991 has now become one of the best known smaller conferences on Computational Intelligence in the world. It fact, it was (to my best knowledge) the ?rst conference to use this term, in 1994, although I confess that another, larger conference was announced ?rst and the trade mark “Computational Intelligence was not coined in Dortmund. I believe, that the success of this conference is grounded on the quality of its reviewedandinvitedpapersaswellasitsgoodorganization. Fromthebeginning, we have sent every paper anonymously to ?ve referees, and we have always accepted only around 50% of the papers sent in. This year it was a little less than that. I would like to thank everybody who helped us by considering Dortmund’s Fuzzy Days as the conference at which to appear. I know that among the - stracts not accepted there were some quite good ones, but we were restricted to a ?xed number. I also know that referees do a good job but cannot always judge wisely from abstracts. Hence my apologies to those who did not make it this year. Please try again! I would like to point out that our conference also has a good regional re- tation. I am grateful to the City of Dortmund, its Lord Mayor Dr. Langemeyer, the Dortmund project, the DFG – Deutsche Forschungsgemeinschaft, the KVR – Kommunalverband Ruhrgebiet, the Martin-Schmeißer-Stiftung, and the C- line AG/Quantum GmbH for their valuable support.

This Festschrift was published in honor of Egon Börger on the occasion of his 75th birthday. It acknowledges Prof. Börger's inspiration as a scientist, author, mentor, and community organizer. Dedicated to a pioneer in the fields of logic and computer science, Egon Börger's research interests are unusual in scope, from programming languages to hardware architectures, software architectures, control systems, workflow and interaction patterns, business processes, web applications, and concurrent systems. The 18 invited contributions in this volume are by leading researchers in the areas of software engineering, programming languages, business information systems, and computer science logic.

This book constitutes the refereed proceedings of the 17th European Conference on Symbolic and Quantitative Approaches to Reasoning with Uncertainty, ECSQARU 2023, held in Arras, France, in September 2023. The 35 full papers presented in this volume were carefully reviewed and selected from 46 submissions. The papers are organized in topical sections about Complexity and Database Theory; Formal Concept Analysis: Theoretical Advances; Formal Concept Analysis: Applications; Modelling and Explanation; Semantic Web and Graphs; Posters.