Varieties of groupoids associated with involuted restrictive bisemigroups of binary relations.
Varieties of idempotent groupoids with small clones
We give an equational description of all idempotent groupoids with at most three essentially n-ary term operations.
Varieties of idempotent slim groupoids
Idempotent slim groupoids are groupoids satisfying and . We prove that the variety of idempotent slim groupoids has uncountably many subvarieties. We find a four-element, inherently nonfinitely based idempotent slim groupoid; the variety generated by this groupoid has only finitely many subvarieties. We investigate free objects in some varieties of idempotent slim groupoids determined by permutational equations.