Complete hypergroups, 1-hypergroups and fuzzy sets.
In a groupoid, consider arbitrarily parenthesized expressions on the variables where each appears once and all variables appear in order of their indices. We call these expressions -ary formal products, and denote the set containing all of them by . If are distinct, the statement that and are equal for all values of is a generalized associative law. Among other results, we show that many small groupoids are completely dissociative, meaning that no generalized associative law holds...
A ternary ring is an algebraic structure of type satisfying the identities and where, moreover, for any , , there exists a unique with . A congruence on is called normal if is a ternary ring again. We describe basic properties of the lattice of all normal congruences on and establish connections between ideals (introduced earlier by the third author) and congruence kernels.
In this short note, it is shown that if are -connected transversals for a finite subgroup of an infinite group such that the index of in is at least 3 and whenever and then is a normal abelian subgroup of .
Let be a positive integer. An algebra is said to have the property if all of its subalgebras generated by two distinct elements have exactly elements. A variety of algebras is a variety with the property if every member of has the property . Such varieties exist only in the case of prime power. By taking the universes of the subalgebras of any finite algebra of a variety with the property , , blocks of Steiner system of type are obtained. The stated correspondence between Steiner...
We give a short account of the construction and properties of left neofields. Most useful in practice seem to be neofields based on the cyclic group and particularly those having an additional divisibility property, called D-neofields. We shall give examples of applications to the construction of orthogonal latin squares, to the design of tournaments balanced for residual effects and to cryptography.