Indistinguishability operators are essential tools in fuzzy logic since they fuzzify the concepts of equivalence relation and crisp equality. This book collects all the main aspects of these operators in a single volume for the first time. The stress is put on the study of their structure and the monograph starts presenting the different ways in which indistinguishability operators can be generated and represented. Special attention is paid to the Representation Theorem and the Sup-T product. Extensionality of fuzzy subsets is studied in detail and is related to their observability and to the granularity. The metric behaviour of indistinguishability operators and their connection with cluster analysis and hierarchical trees is established. Different ways to aggregate such operators are given as well as a number of methods to obtain transitive approximations of a fuzzy relation. Applications to approximate reasoning and to the study of fuzzy subgroups are also provided. The book ends with a chapter on finite-valued indistinguishability operators.

This book collects the abstracts of the contributions presented at AGOP 2017, the 9th International Summer School on Aggregation Operators. The conference took place in Skövde (Sweden) in June 2017. Contributions include works from theory and fundamentals of aggregation functions to their use in applications. Aggregation functions are usually defined as those functions that are monotonic and that satisfy the unanimity condition. In particular settings these conditions are relaxed. Aggregation functions are used for data fusion and decision making. Examples of these functions include means, t-norms and t-conorms, copulas and fuzzy integrals (e.g., the Choquet and Sugeno integrals).

This book is a printed edition of the Special Issue "New Trends in Fuzzy Set Theory and Related Items" that was published in Axioms

Soft computing is a new, emerging discipline rooted in a group of technologies that aim to exploit the tolerance for imprecision and uncertainty in achieving solutions to complex problems. The principal components of soft computing are fuzzy logic, neurocomputing, genetic algorithms and probabilistic reasoning.This volume is a collection of up-to-date articles giving a snapshot of the current state of the field. It covers the whole expanse, from theoretical foundations to applications. The contributors are among the world leaders in the field.

Fuzzy Sets, Logics and Reasoning about Knowledge reports recent results concerning the genuinely logical aspects of fuzzy sets in relation to algebraic considerations, knowledge representation and commonsense reasoning. It takes a state-of-the-art look at multiple-valued and fuzzy set-based logics, in an artificial intelligence perspective. The papers, all of which are written by leading contributors in their respective fields, are grouped into four sections. The first section presents a panorama of many-valued logics in connection with fuzzy sets. The second explores algebraic foundations, with an emphasis on MV algebras. The third is devoted to approximate reasoning methods and similarity-based reasoning. The fourth explores connections between fuzzy knowledge representation, especially possibilistic logic and prioritized knowledge bases. Readership: Scholars and graduate students in logic, algebra, knowledge representation, and formal aspects of artificial intelligence.

The functional equation of associativity is the topic of Abel's first contribution to Crelle's Journal. Seventy years later, it was featured as the second part of Hilbert's Fifth Problem, and it was solved under successively weaker hypotheses by Brouwer (1909), Cartan (1930) and Aczel (1949). In 1958, B Schweizer and A Sklar showed that the ?triangular norms? introduced by Menger in his definition of a probabilistic metric space should be associative; and in their book Probabilistic Metric Spaces, they presented the basic properties of such triangular norms and the closely related copulas. Since then, the study of these two classes of functions has been evolving at an ever-increasing pace and the results have been applied in fields such as statistics, information theory, fuzzy set theory, multi-valued and quantum logic, hydrology, and economics, in particular, risk analysis.This book presents the foundations of the subject of associative functions on real intervals. It brings together results that have been widely scattered in the literature and adds much new material. In the process, virtually all the standard techniques for solving functional equations in one and several variables come into play. Thus, the book can serve as an advanced undergraduate or graduate text on functional equations.

This volume collects the extended abstracts of 45 contributions of participants to the Seventh International Summer School on Aggregation Operators (AGOP 2013), held at Pamplona in July, 16-20, 2013. These contributions cover a very broad range, from the purely theoretical ones to those with a more applied focus. Moreover, the summaries of the plenary talks and tutorials given at the same workshop are included. Together they provide a good overview of recent trends in research in aggregation functions which can be of interest to both researchers in Physics or Mathematics working on the theoretical basis of aggregation functions, and to engineers who require them for applications.

This book furthers the historical and technical debate by looking at reasoning as the action of language when it is devoted to explaining or foretelling, based on the authors’ centennial combined experience in fuzzy logic. A simple logical model mixing abductions and deductions is introduced in order to attain speculations, conjectures that may be responsible for induction, and creativity in reasoning. A central point and a dire hypothesis of the book are that such process can be implemented by computation and as such can lead to a new approach to automatic thinking and reasoning. On top of the technical approach, the relationship between reasoning and thinking is also analyzed trying to establish links with notions and concepts of thinkers from the European Middle Age to the current days. This book is recommended to young researchers that are interested in either the scientific or philosophical aspects of computational thinking, and can further the debate between the two approaches.

Since it was formed in 1994, the Catalan Association for Artificial Intelligence (ACIA) has been promoting cooperation between researchers in artificial intelligence within the Catalan speaking community. The association now holds an annual conference in the Catalan region, which aims to foster discussion of the latest developments in artificial intelligence within the community of Catalan countries, as well as amongst members of the wider AI community. This book presents the proceedings of the 18th International Conference (CCIA 2015), held in Valencia, Spain, in October 2015. It contains full versions of the peer reviewed papers presented at the conference, as well as shorter poster contributions. In addition to this year’s dominant research trends of classification, decision support systems and data mining, many other topics are covered, ranging from theoretical aspects to descriptions of real applications. This overview of current work in the Catalan artificial intelligence community and of the collaboration between ACIA members and the AI community worldwide will be of interest to all those working in the field of artificial intelligence.

The Second World Conference on Mathematics at the Service of Man was held at the Universidad Politecnica de Las Palmas, Canary Islands, Spain, June 28 to July 3, 1982. The first volume of the Proceedings of the Conference, entitled "Functional Equations-Theory and Applications" has appeared in the Reidel series "Mathematics and Its Applications". The papers in this volume consist of the invited lectures delivered at the Conference, Section 7: Non-Classical Logics and Modelling, as well as some selected papers which offer an introduction to the philosophy, methodology and to the lite rature of the broad and fascinating field of vagueness, imprecision and uncertainty. The contributed papers appeared in the volume of photo-offset preprints distributed at the Conference. It is our hope that the papers present a good sample with respect to the background, the formalism and practice of this area of research as far as we understand it today. As the subject "Vagueness" touches many aspects of human thinking, the contributions have been made from a broad spectrum ranging from philo~ophy through pure mathematics to probability theory and mathematical economics, therefore the careful reader should find some new insights here. In conclusion, the editors want to thank all authors who have contributed to this volume; the publishers of "Commenta tiones Mathematicae Universitatis Carolinae" for permission to reprint the paper "Fuzziness and Fuzzy Equality", Commentationes Mathematicae Universitatis Carolinae 23 (1982), 249-267, and D. Reidel for friendly cooperation.