Relational structures and dependence spaces
Relations and topologies
Relations, coverings, hypergraphs and matroids
Relations With I-structure in Categories With Pullbacks
Schreier-Zassenhaus theorem for algebras. II
Some remarks on distributive groupoids
Span in incidence structures of independent sets defined on projective space
Special incidence structures of type
Special incidence structures of type . II.
Statistical linear spaces. I. Properties of , -topology
Statistical linear spaces. II. Strongest -norm
Structures Algebraiques munis, avec des lois de composition generalisees - Generalisations du produit scalaire
Subtraction semigroups
A subtraction semigroup is a semigroup with a further operation "" added, called subtraction and satisfying certain axioms. The paper concerns a problem by B. M. Schein concerning the structure of multiplication in a subtraction semigroup.
Subtractive groupoids and TST-spaces
Ternary semigroups of morphisms of objects in categories
In this paper the notion of a ternary semigroup of morphisms of objects in a category is introduced. The connection between an isomorphism of categories and an isomorphism of ternary semigroups of morphisms of suitable objects in these categories is considered. Finally, the results obtained for general categories are applied to the categories and which were studied in [5].
Ternary structures and groupoids
Ternary structures and partial semigroups
The algebraic uniqueness of the addition of natural numbers.
The Słupecki criterion by duality
A method is presented for proving primality and functional completeness theorems, which makes use of the operation-relation duality. By the result of Sierpiński, we have to investigate relations generated by the two-element subsets of only. We show how the method applies for proving Słupecki’s classical theorem by generating diagonal relations from each pair of k-tuples.
Tolerance lattice of algebras with restricted similarity type