منابع مشابه
Weak Del Pezzo Surfaces with Irregularity
I construct normal del Pezzo surfaces, and regular weak del Pezzo surfaces as well, with positive irregularity q > 0. This can happen only over nonperfect fields. The surfaces in question are twisted forms of nonnormal del Pezzo surfaces, which were classified by Reid. The twisting is with respect to the flat topology and infinitesimal group scheme actions. The twisted surfaces appear as generi...
متن کاملWeak Del Pezzo with Irregularity
I construct normal del Pezzo surfaces, and regular weak del Pezzo surfaces as well, with positive irregularity q > 0. Such things can happen only over nonperfect fields. The surfaces in question are twisted forms of nonnormal del Pezzo surfaces, which were classified by Reid. The twisting is with respect to the flat topology and infinitesimal group scheme actions. The twisted surfaces appear as...
متن کاملNonnormal Del Pezzo Surfaces
0.1 Throughout this paper, a del Pezzo surface is by definition a connected, 2-dimensional, projective k-scheme X,OX(1) that is Gorenstein and anticanonically polarised; in other words, X is Cohen–Macaulay, and the dualising sheaf is invertible and antiample: ωX ∼= OX(−1). For example, X = X3 ⊂ P 3 an arbitrary hypersurface of degree 3. Under extra conditions, del Pezzo surfaces are interesting...
متن کاملWeak Approximation for Low Degree Del Pezzo Surfaces
Let K = Func(C) be the function field of a smooth curve C. For every Del Pezzo surface S/K which is an appropriately generic, weak approximation for S holds at every place of K, i.e., for every closed point c of C. This combines earlier work in (arXiv:0810.2597) with an analysis of weak approximation near boundary points of the parameter spaces for Del Pezzo surfaces of degrees 1 and 2.
متن کاملWeak Approximation for General Degree Two Del Pezzo Surfaces
We address weak approximation for certain del Pezzo surfaces defined over the function field of a curve. We study the rational connectivity of the smooth locus of degree two del Pezzo surfaces with two A1 singularities in order to prove weak approximation for degree two del Pezzo surfaces with square-free discriminant.
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ژورنال
عنوان ژورنال: Tohoku Mathematical Journal
سال: 2007
ISSN: 0040-8735
DOI: 10.2748/tmj/1182180737