For two propositional fuzzy logics, we present analytic proof calculi, based on relational hypersequents. The logic considered first, called Mà L, is based on the finite ordinal sums of à Lukasiewicz t-norms. In addition to the usual connectives – the conjunction ̄, the implication →, and the constant 0 –, we use a further unary connective interpreted by the function associating with each truth...

In this paper we present an O(nk) procedure, Algorithm MR3, for computing k eigenvectors of an n× n symmetric tridiagonal matrix T . A salient feature of the algorithm is that a number of different LDLt products (L unit lower triangular, D diagonal) are computed. In exact arithmetic each LDLt is a factorization of a translate of T . We call the various LDLt products representations (of T ) and,...

Analytical structure for a fuzzy PID controller is introduced by employing two fuzzy sets for each of the three input variables and four fuzzy sets for the output variable. This structure is derived via left and right trapezoidal membership functions for inputs, trapezoidal membership functions for output, algebraic product triangular norm, bounded sum triangular co-norm, Mamdani minimum infere...

In this paper we formulate and analyze a discretization method for a 2D linear singularly perturbed convection-diffusion problem with a singular perturbation parameter ε. The method is based on a nonconforming combination of the conventional Galerkin piecewise linear triangular finite element method and an exponentially fitted finite volume method, and on a mixture of triangular and rectangular...

In order to avoid combinatorial rule explosion in fuzzy reasoning, in this work we explore the distributive equations of implications. In details, by means of the section of I, we give out the sufficient and necessary conditions of solutions for the distributive equation of implication I(x, T1(y, z)) = T2(I(x, y), I(x, z)), when T1 is a continuous but not Archimedean triangular norm, T2 is a co...

Periods of matrix power sequences in max-drast fuzzy algebra and methods of their computation are considered. Matrix power sequences occur in the theory of complex fuzzy systems with transition matrix in max-t algebra, where t is a given triangular fuzzy norm. Interpretation of a complex system in max-drast algebra reflects the situation when extreme demands are put on the reliability of the sy...

In this paper we introduce and describe two classes of aggregation functions with members that are migrative. First continuous triangular norms are studied that own the migrative property with respect to another fixed t-norm, in particular to the three prototypes minimum, product, and the Łukasiewicz t-norm. For classes of nilpotent and strict migrative t-norms the characterization and construc...

In 2000, Figallo and Sanza introduced the n×m−valued Lukasiewicz-Moisil algebras, which are a particular case of Matrix Lukasiewicz algebras, and a nontrivial generalization of n−valued Lukasiewicz-Moisil algebras. Here we start a research on the class of n × m−valued Lukasiewicz-Moisil algebras endowed with two modal operators (or 2mLMn×m−algebras). These algebras constitute a common generaliz...

Rough set theory is an important tool for dealing with granularity and vagueness in information systems. This paper studies a kind of rough set algebra. The collection of all the rough sets of an approximation space can be made into a 3-valued Lukasiewicz algebra. We call the algebra a rough 3-valued Lukasiewicz algebra. In this paper, we focus on the rough 3-valued Lukasiewicz algebras, which ...

It has been developed a C++ program that generates random fuzzy relations of a given dimension and computes their T-transitive closure (that contains the initial relation) and the new T-transitivized relation (that is contained in the initial relation) for the t-norms minimum, product and Lukasiewicz. It has been computed several distances between both transitive closure and transitivized relat...