polynomial ring 6 16S36 5 16W20 4 skew polynomial ring 4 derivation 3 $PBW$ bases 2 16N40 2 16S30 2 16S80 2 16S80; Secondary: 16S30 2 16U99 2 17B66 2 20D15 2 20E22 2 20E36 2 20F14 2 Primary 13N15; Secondary 13A99 2 Primary: 16S10 2 RNP ring 2 \(H\)-separable polynomial 2 central series 2 divergence 2 finite field 2 jacobian derivation 2 nilpotent group 2 quantum algebras 2 separable extension 2 skew $PBW$ extensions 2 skew PBW extension 2 skew polynomial rings 2