Cauchon diagrams for quantized enveloping algebras
| dc.creator | Mériaux, Antoine | |
| dc.date | 2008-07-07 | |
| dc.date | 2009-02-10 | |
| dc.date.accessioned | 2026-07-07T12:39:07Z | |
| dc.date.available | 2026-07-07T12:39:07Z | |
| dc.description | Let $\mathfrak{g}$ be a finite dimensional complex simple Lie algebra, $\mathbb{K}$ a commutative field and $q$ a nonzero element of $\mathbb{K}$ which is not a root of unity. To each reduced decomposition of the longest element $w_0$ of the Weyl group $W$ corresponds a PBW basis of the quantised enveloping algebra $\mathcal{U}_q^+(\mathfrak{g})$, and one can apply the theory of deleting-derivation to this iterated Ore extension. In particular, for each decomposition of $w_0$, this theory constructs a bijection between the set of prime ideals in $\mathcal{U}_q^+(\mathfrak{g})$ that are invariant under a natural torus action and certain combinatorial objects called Cauchon diagrams. In this paper, we give an algorithmic description of these Cauchon diagrams when the chosen reduced decomposition of $w_0$ corresponds to a good ordering (in the sense of Lusztig \cite{Lu2}) of the set of positive roots. This algorithmic description is based on the constraints that are coming from Lusztig's admissible planes \cite{Lu2}: each admissible plane leads to a set of constraints that a diagram has to satisfy to be Cauchon. Moreover, we explicitely describe the set of Cauchon diagrams for explicit reduced decomposition of $w_0$ in each possible type. In any case, we check that the number of Cauchon diagrams is always equal to the cardinal of $W$. In \cite{CM}, we use these results to prove that Cauchon diagrams correspond canonically to the positive subexpressions of $w_0$. So the results of this paper also give an algorithmic description of the positive subexpressions of any reduced decomposition of $w_0$ corresponding to a good ordering. | |
| dc.description | The section 4 was rewritten and split into section 4 and 5 for more clarity. An english version is now available | |
| dc.identifier | https://arxiv.org/abs/0807.1012 | |
| dc.identifier | http://arxiv.org/abs/0807.1012 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/218998 | |
| dc.subject | Quantum Algebra | |
| dc.subject | 17B37; 16W35 | |
| dc.title | Cauchon diagrams for quantized enveloping algebras | |
| dc.type | text |