On closed sets of relational constraints and classes of functions closed under variable substitutions

On Closed Sets of Relational Constraints and Classes of Functions Closed under Variable Substitutions

Pippenger’s Galois theory of finite functions and relational constraints is extended to the infinite case. The functions involved are functions of several variables on a set A and taking values in a possibly different set B, where any or both of A and B may be finite or infinite.

Closed Classes of Functions, Generalized Constraints and Clusters

Classes of functions of several variables on arbitrary non-empty domains that are closed under permutation of variables and addition of dummy variables are characterized in terms of generalized constraints, and hereby Hellerstein’s Galois theory of functions and generalized constraints is extended to infinite domains. Furthermore, classes of operations on arbitrary non-empty domains that are cl...

On Pre-θ-Open Sets and Two Classes of Functions

Some Generalizations of Locally Closed Sets

Arenas et al. [1] introduced the notion of lambda-closed sets as a generalization of locally closed sets. In this paper, we introduce the notions of lambda-locally closed sets, Lambda_lambda-closed sets and lambda_g-closed sets and obtain some decompositions of closed sets and continuity in topological spaces.

Some new properties of fuzzy strongly ${{g}^{*}}$-closed sets and $delta {{g}^{*}}$-closed sets in fuzzy topological spaces

‎In this paper, a new class of fuzzy sets called fuzzy strongly ${{g}^{*}}$-closed sets is introduced and its properties are investigated. Moreover, we study some more properties of this type of closed spaces.