Посилання:Isolated and nilpotent subsemigroups in the variants of ISn / G. Tsyaputa // Algebra and Discrete Mathematics. — 2006. — Vol. 5, № 1. — С. 89–97. — Бібліогр.: 9 назв. — англ.
All isolated, completely isolated, and nilpotent
subsemigroups in the semigroup ISn of all injective partial transformations of an n-element set, considered as a semigroup with a
sandwich multiplication are described.