Unramified Galois Coverings of Algebraic Curves
نویسندگان
چکیده
منابع مشابه
ON UNRAMIFIED COVERINGS OF MAXIMAL CURVES by
— We investigate unramified coverings of algebraic curves over a finite field, specially in relation with maximal curves and the question whether maximal curves are covered by the Hermitian curve. Résumé (Sur les revêtements non-ramifiés des courbes maximales). — Nous étudions les revêtements non-ramifiés de courbes algébriques sur un corps fini, en particulier de courbes maximales. Nous nous p...
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We discuss sufficient conditions for a given curve to be covered by a maximal curve with the covering being unramified; it turns out that the given curve itself will be also maximal. We relate our main result to the question of whether or not a maximal curve is covered by the Hermitian curve. We also provide examples illustrating the results. §1. Let X be a projective, geometrically irreducible...
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Let X → Y be a Galois covering of curves, where the genus of X is ≥ 2 and the genus of Y is ≤ 2. We prove that under certain hypotheses, X has an unramified cover that dominates a hyperelliptic curve; our results apply, for instance, to all tamely superelliptic curves. Combining this with a theorem of Bogomolov and Tschinkel shows that X has an unramified cover that dominates y = x − 1, if char...
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(1b) Question. For which pairs (C0,H) does a lift exist? Note that the lifting problem for C0 is formally smooth. However we will see that in general the lifting problem for (C0,H) can be obstructed; in some cases a lifting does not exist, in several cases ramification in R is needed to make a lifting possible. In order to have a positive answer to this question it suffices to consider the case...
متن کاملGalois Module Structure of Unramified Covers
Let G be a finite group. Suppose that Y is a projective algebraic variety over Z (i.e an integral scheme which is projective and flat over Spec (Z)) of relative dimension d. In this paper, we consider finite Galois covers π : X → Y with group G which are everywhere unramified, i.e “G-torsors”. Let F be a G-equivariant coherent sheaf on X. Consider the value of the right derived global section f...
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ژورنال
عنوان ژورنال: Journal of Number Theory
سال: 1995
ISSN: 0022-314X
DOI: 10.1006/jnth.1995.1087