“…Section 2 contains the generalization of all the results obtained by Bhat in [5], [6] and [7], from Ore extensions of automorphism type to bijective skew PBW extensions. The Σ-rigid rings and the weak Σ-rigid rings defined by the second author in [47] and [54], respectively, are key in this generalization (they are the corresponding generalization of σ-rigid rings and weak σ-rigid rings, respectively). Also, in this section, we define the Σ( * )-rings as a natural generalization of σ( * )-rings.…”