Apart from simple Ore extensions such as the Weyl algebras, the best known example of a primitive Ore extension is the universal enveloping algebra U(g) of the 2-dimensional solvable Lie algebra g over a field k of characteristic zero, see [4, p. 22]. U(g) is a polynomial algebra over k in two indeterminates x and y with multiplication subject to the relation xy – yx = y, and may be regarded either as an Ore extension of k [x] by the k-automorphism which maps x to x – 1 or as an Ore extension of k[y] by the derivation yd/dy. The argument suggested in [4, p. 22] to prove the primitivity of U(g) can easily be generalised [6] to show that, if α is an automorphism of the ring R then the following conditions are sufficient for R[x, α] to be primitive: (i) no power αs, s ≧ 1, of α is inner; (ii) the only ideals of R invariant under α are 0 and R. These conditions are necessary and sufficient for the simplicity of the skew Laurent polynomial ring R[x, x–1, α] but are not necessary for the primitivity of R[x, α] (the ordinary polynomial ring D[x] over a division ring D not algebraic over its centre is easily seen to be primitive).
@article{10_1017_S0017089500003086,
author = {Jordan, D. A.},
title = {Primitive {Ore} extensions},
journal = {Glasgow mathematical journal},
pages = {93--97},
year = {1977},
volume = {18},
number = {1},
doi = {10.1017/S0017089500003086},
url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500003086/}
}
TY - JOUR
AU - Jordan, D. A.
TI - Primitive Ore extensions
JO - Glasgow mathematical journal
PY - 1977
SP - 93
EP - 97
VL - 18
IS - 1
UR - http://geodesic.mathdoc.fr/articles/10.1017/S0017089500003086/
DO - 10.1017/S0017089500003086
ID - 10_1017_S0017089500003086
ER -
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