ScalingStacks

Examples 5.5 . [02ES]

Original official author HTML, exact retained edition. Historical TeX conversion verdicts remain unchanged. Cited-edition alignment and mathematical self-containment are not assessed.

Complete original source context · Original author HTML

Examples 5.5.

Let SS be a normal algebraic surface. The following are equivalent:

  1. (1)

    SS has only canonical singularities.

  2. (2)

    SS is locally analytically isomorphic to X=ℂ2/GX=\mathbb{C}^{2}/G, G⊂S​L2​(ℂ)G\subset SL_{2}(\mathbb{C}) a finite subgroup.

  3. (3)

    The exceptional divisors of the minimal resolution πm​i​n\pi_{min} of SS, have simple normal crossings, their components are (-2) smooth rational curves, their incidence graphs are of type A-D-E (Du Val singularities).

The log terminal surface singularities are precisely the singularities of the form X=ℂ2/GX=\mathbb{C}^{2}/G, G⊂G​L2​(ℂ)G\subset GL_{2}(\mathbb{C}) a finite subgroup.

Original mathematics by the credited authors. Source-backed reader collection; mathematical self-containment is not assessed.