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Deformations of type D Kleinian singularities

Paul Boddington
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Abstract

For $n\geq 4$ we shall construct a family $D(q)$ of non-commutative deformations of the coordinate algebra of a Kleinian singularity of type $D_n$ depending on a polynomial $q$ of degree $n$. We shall prove that every deformation of a type $D$ Kleinian singularity which is not commutative is isomorphic to some $D(q)$. We shall then consider in type $D$ the family of deformations $\mathcal{O}^{\boldsymbolλ}$ constructed by Crawley-Boevey and Holland. For each $\mathcal{O}^{\boldsymbolλ}$ which is not commutative we shall exhibit an explicit isomorphism $D(q)\cong \mathcal{O}^{\boldsymbolλ}$ for a suitable choice of $q$. This will enable us to prove that every deformation of a Kleinian singularity of type $D_n$ is isomorphic to some $\mathcal{O}^{\boldsymbolλ}$ and determine when two $\mathcal{O}^{\boldsymbolλ}$ are isomorphic.

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Paul Boddington. 2007-12-21. Deformations of type D Kleinian singularities. https://arxiv.org/abs/math/0612853

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