Banakh, T.T.; Gavrylkiv, V.; Nykyforchyn, O.
(Algebra and Discrete Mathematics, 2008)
Given a group X we study the algebraic structure of its superextension λ(X). This is a right-topological semigroup consisting of all maximal linked systems on X
endowed with the operation
A∘B={C⊂X:{x∈X:x−1C∈B}∈A}
...