Completions of $\C^*$-surfaces

dc.creatorFlenner, Hubert
dc.creatorKaliman, Shulim
dc.creatorZaidenberg, Mikhail
dc.date2005-11-10
dc.date.accessioned2026-07-07T06:51:07Z
dc.date.available2026-07-07T06:51:07Z
dc.descriptionFollowing an approach of Dolgachev, Pinkham and Demazure, we classified in math.AG/0210153 normal affine surfaces with hyperbolic $\C^{*}$-actions in terms of pairs of $\Q$-divisors $(D_+,D_-)$ on a smooth affine curve. In the present paper we show how to obtain from this description a natural equivariant completion of these $\C^*$-surfaces. Using elementary transformations we deduce also natural completions for which the boundary divisor is a standard graph in the sense of math.AG/0511063 and show in certain cases their uniqueness. This description is especially precise in the case of normal affine surfaces completable by a zigzag i.e., by a linear chain of smooth rational curves. As an application we classify all zigzags that appear as boundaries of smooth or normal $\C^*$-surfaces.
dc.description37 pages
dc.identifierhttps://arxiv.org/abs/math/0511282
dc.identifierhttp://arxiv.org/abs/math/0511282
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/104881
dc.subjectAlgebraic Geometry
dc.subject14R05, 14R20, 14J50
dc.titleCompletions of $\C^*$-surfaces
dc.typetext

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