Proper cores and dominance cores of fuzzy games

Many kinds of proper cores and dominance cores of fuzzy games are proposed in this paper. We also consider two similar concepts of payoff of a fuzzy coalition that are called the true payoff and quasi-payoff. The different concepts of proper cores and dominance cores will be proposed based on the true payoff and quasi-payoff of a fuzzy coalition. Some mild sufficient conditions are provided in this paper to guarantee the equalities of different proper cores and dominance cores.     

Fuzzy topology on fuzzy sets: Product fuzzy topology and fuzzy topological groups

The notion of product fuzzy topology in the case of fuzzy topology on fuzzy sets is introduced and the product invariance of fuzzy Hausdorffness, compactness, connectedness are examined. The product fuzzy topology is used to define fuzzy group topology on a fuzzy subgroup of a group G and some properties of fuzzy topological groups are obtained.     

Fuzzy relation equations theory as a basis of fuzzy modelling: An overview

We give a wide overview on the applications of fuzzy relation equations theory to decision-making processes, to the construction of preference relations and to Knowledge Engineering, mainly fuzzy control and fuzzy pattern recognition. General theoretical results and methodological aspects are pointed out.     

Fuzzy relations and fuzzy functions

In this paper, we apply the standard element free mathematical definitions of equivalence relation and function as relations to the case of fuzzy relations. One of the surprising results of this approach is that fuzzy functions take their values from the complemented elements of a Brouwerian lattice. Thus, in the common case of the values being taken from the unit interval, the only fuzzy functions of this type are the ordinary functions. This might suggest that fuzzy set theory is more than just a generalization of ordinary set theory.     

Fuzzy cores and fuzzy balancedness

We study the relation between the fuzzy core and balancedness for fuzzy games. For regular games, this relation has been studied by Bondareva (Problemy Kibernet 10:119–139, 1963) and Shapley (Naval Res Logist Q 14: 453–460, 1967). First, we gain insight in this relation when we analyse situations where the fuzzy game is continuous. Our main result shows that any fuzzy game has a non-empty core if and only if it is balanced. We also consider deposit games to illustrate the use of the main result.     

Inconsistency indices for pairwise comparisons and the Pareto dominance principle

We consider the problem of quantifying inconsistency in pairwise comparisons and valued-preferences. A wide range of indices have been proposed in the literature to perform this task, and two sets of conditions have been introduced to validate such indices. We summarize some criticisms from the literature and we add more evidence to show that neither of the two systems is adequate in its current formulation. Thanks to the widely accepted concept of weak Pareto dominance, we formulate a new property. We argue that a simple regularity condition and this new property can overcome the shortcomings of the two axiomatic systems, and represents a significantly simpler framework. Finally, we claim that, if we had resorted to strict Pareto dominance, we would have needed just one axiom.     

Fuzzy folding of fuzzy horocycle

In this paper, we will give a new definition for folding of fuzzy horocycle. It introduces the concept of fuzzy horocycle. Also we will deduce the relation between the folding of fuzzy circles and fuzzy horocycles. Theorems governing this type of folding are deduced.     

Fuzzy invariant subgroups and fuzzy ideals

The purpose of this paper is to introduce some basic concepts of fuzzy algebra, as fuzzy invariant subgroups, fuzzy ideals, and to prove some fundamental properties. In particular, it will give a characteristic of a field by a fuzzy ideal.     

Fuzzy topological spaces and fuzzy compactness

It is the purpose of this paper to go somewhat deeper into the structure of fuzzy topological spaces. In doing so we found we had to alter the definition of a fuzzy topology used up to now. We shall also introduce two functors $\text{}\text{?}$gw and $\text{}\text{?}$gi which will allow us to see more clearly the connection between fuzzy topological spaces and topological spaces. Finally we shall introduce the concept of fuzzy compactness as the generalization of compactness in topology. It will be shown in a following publication that contrary to the results obtained up to now, the Tychonoff-product theorem is safeguarded with fuzzy compactness.     

Fuzzy uniqueness of fuzzy mappings

For fuzzy mappings between fuzzy sets of higher level we study a notion of fuzzy uniqueness. i.e. of fuzzy functions, which formalizes the intuition that ‘almost identical’ images under f.Characterizations are given for such fuzzy mappings which are really (i.e. with truth value 1) fuzzy unique or fuzzy biunique, and for those fuzzy sets which can be domains of really fuzzy unique fuzzy mappings.Finally, as an application fuzzy cardinals, their ordering, sum, and product are introduced, and some properties proved.     

Fuzzy measure of fuzzy events defined by fuzzy integrals

We define the concept of fuzzy measure of a fuzzy event by using a general form of fuzzy integral proposed by Murofushi, called fuzzy t-conorm integral, encompassing previous definitions. Zadeh defined the probability measure of a fuzzy event, and later the possibility measure of fuzzy event. Using a duality property of fuzzy t-conorm integral, we propose a general definition of fuzzy measure of fuzzy events, which is compatible with previous definitions of Zadeh, and possesses all properties of a fuzzy measure, in particular the duality property. Using our definition, we examine the case of decomposable measures and belief functions. A comparison with previous works is provided.     

Performance evaluation: An integrated method using data envelopment analysis and fuzzy preference relations

In a multi-attribute decision-making (MADM) context, the decision maker needs to provide his preferences over a set of decision alternatives and constructs a preference relation and then use the derived priority vector of the preference to rank various alternatives. This paper proposes an integrated approach to rate decision alternatives using data envelopment analysis and preference relations. This proposed approach includes three stages. First, pairwise efficiency scores are computed using two DEA models: the CCR model and the proposed cross-evaluation DEA model. Second, the pairwise efficiency scores are then utilized to construct the fuzzy preference relation and the consistent fuzzy preference relation. Third, by use of the row wise summation technique, we yield a priority vector, which is used for ranking decision-making units (DMUs). For the case of a single output and a single input, the preference relation can be directly obtained from the original sample data. The proposed approach is validated by two numerical examples.     

Fuzzy proximity structures and fuzzy ultrafilters

For a population genetic model with differential fertility it is shown that every solution tends to equilibrium. A simple argument for quasimonotone systems, which is interesting itself, allows the extension of earlier partial results, obtained via Dulac's criterion, to the entire parameter space. A similar argument excludes stable limit cycles in higher dimensions.