On the nilpotency of the Jacobson radical of semigroup rings.
In this note, for a ring endomorphism and an -derivation of a ring , the notion of weakened -skew Armendariz rings is introduced as a generalization of -rigid rings and weak Armendariz rings. It is proved that is a weakened -skew Armendariz ring if and only if is weakened -skew Armendariz if and only if is weakened -skew Armendariz ring for any positive integer .
Let k be a commutative field. For any a,b∈ k, we denote by the deformation of the 2-dimensional Weyl algebra over k associated with the Jordanian Hecke symmetry with parameters a and b. We prove that: (i) any can be embedded in the usual Weyl algebra A₂(k), and (ii) is isomorphic to A₂(k) if and only if a = b.