In the beginning are defined
right differential operators for noncommutative algebras. Differential operators give
rise to right derivalions, jet and Kähler modules for noncommutative algebras,
differential separability and differential inseparability (called differentially stacked).
Differential separability is related to the abelianized algebra being separable,
Differentially stacked is related to pure inseparability of noncommutative
algebras.