The proof of Lemma 3.1 in Section 3 is valid only for v = 1. In fact, in the case of v 2 2, the assertion of Corollary 3.3 to the lemma contradicts with the supersingularity. Indeed, this corollary asserted that there exists a nontrivial extension of OC by OC such that its pull-back by the p -t h po
False Hyperelliptic Surfaces with Section
β Scribed by Yoshifumi Takeda Nara
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 847 KB
- Volume
- 167
- Category
- Article
- ISSN
- 0025-584X
No coin nor oath required. For personal study only.
β¦ Synopsis
Abstract
Let X be a nonsingular relatively minimal projective surface over an algebraically closed field of characteristic p > 0. We call X a false hyperelliptic surface if X satisfies the following conditions: (1) c~2~(X) = 0, c~1~(X)^2^ = 0, dim Alb (X) = 1, and (2) All fibres of the Albanese mapping of X are rational curves with only one cusp of type x____p^v^ + y^n^ = 0. In this article, we consider a false hyperelliptic surface whose Albanese mapping has a crossβsection. We prove that every false hyperellyptic surface with section arises from an elliptic ruled surface and that every false hyperelliptic surface has an elliptic fibration with multiple fibre. Moreover, we construct an example of false hyperelliptic surface with section, whose elliptic fibration has a multiple fibre of supersingular elliptic curve of multiplicity p^v^ (v > 1).
π SIMILAR VOLUMES
Optimal upper bounds for the cohomology groups of space curves have been derived recently. Curves attaining all these bounds are called extremal curves. This note is a step to analyze the corresponding problems for surfaces. We state optimal upper bounds for the second and third cohomology groups of