On a class of subdirectly irreducible groupoids
On cyclic hypergroups with period
On Finite-element Simple Extensions of a Countable Collection of Countable Groupoids
On Free Commutative Groupoids
On free commutative groupoids.
On representations of monoids as monoids of polynomials
On rings with zero divisors. Strong -groups
On splitting -systems
On the extension of transi-groups
On the general theory of m-groups
On the generalised equations of associativity and bisymmetry.
On -algebras
One-element extensions of distributive groupoids
-hypergoupes
Polygroupes et Certaines de leurs Proprietes
Qualgebras and knotted 3-valent graphs
This paper is devoted to new algebraic structures, called qualgebras and squandles. Topologically, they emerge as an algebraic counterpart of knotted 3-valent graphs, just like quandles can be seen as an "algebraization" of knots. Algebraically, they are modeled after groups with conjugation and multiplication/squaring operations. We discuss basic properties of these structures, and introduce and study the notions of qualgebra/squandle 2-cocycles and 2-coboundaries. Knotted 3-valent graph invariants...
Quasetrivial and nearly quasitrivial distributive goupoids and semigroups
R-and T-Groupoids: A Generalization of Groups.
Semi-ipergruppi e ipergruppi -completi
Some remarks on distributive groupoids