English

Isomorphism problems and groups of automorphisms for Ore extensions $K[x][y; \delta ]$ (zero characteristic)

Rings and Algebras 2021-07-21 v1

Abstract

Let \L(f)=K[x][y;fddx]\L (f) = K[x][y; f\frac{d}{dx} ] be an Ore extension of a polynomial algebra K[x]K[x] over a field KK of characteristic zero where fK[x]f\in K[x]. For a given polynomial ff, the automorphism group of the algebra \L(f)\L (f) is explicitly described. The polynomial case \L(0)=K[x,y]\L (0) = K[x,y] and the case of the Weyl algebra A1=K[x][y;ddx]A_1= K[x][y; \frac{d}{dx} ] were done done by Jung (1942) and van der Kulk (1953), and Dixmier (1968), respectively. In 1997, Alev and Dumas proved that the algebras \L(f)\L (f) and \L(g)\L (g) are isomorphic iff g(x)=\lf(αx+β)g(x) = \l f(\alpha x+\beta ) for some \l,αK\{0}\l, \alpha \in K\backslash \{ 0\} and βK\beta\in K. In 2015, Benkart, Lopes and Ondrus gave a complete description of the set of automorphism groups of algebras \L(f)\L(f). In this paper we complete the picture, i.e. {\em given} the polynomial ff we have the explicit description of the automorphism group of \L(f)\L (f).

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Cite

@article{arxiv.2107.09401,
  title  = {Isomorphism problems and groups of automorphisms for Ore extensions $K[x][y; \delta ]$ (zero characteristic)},
  author = {V. V. Bavula},
  journal= {arXiv preprint arXiv:2107.09401},
  year   = {2021}
}

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11 pages