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Frobenius order-sequences of curves. (English) Zbl 0824.14019
Frey, Gerhard (ed.) et al., Algebra and number theory. Proceedings of a conference held at the Institute of Experimental Mathematics, University of Essen, Germany, December 2-4, 1992. Berlin: de Gruyter. 27-41 (1994).
Let $$X \subseteq \mathbb{P}^ N$$ be a nondegenerate, absolutely irreducible algebraic curve over $$\mathbb{F}_ q$$. In a previous paper, K.-O. Stöhr and J. F. Voloch [Proc. Lond. Math. Soc., III. Ser. 52, 1- 19 (1986; Zbl 0593.14020)] introduced the notion of “$$q$$-Frobenius order-sequence of $$X$$,” and gave a geometric proof of Weil’s basic theorem on rational points of curves over $$\mathbb{F}_ q$$. The order sequence of $$X$$ is the set of possible intersection multiplicities of $$X$$ with the hyperplanes of $$\mathbb{P}^ N$$ at general points. It is basic that the $$q$$-Frobenius sequence differs from the order sequence by the deletion of one order. The paper being reviewed studies this phenomenon and establishes some geometric results, e.g. on the inseparability degree of Gauss maps.
For the entire collection see [Zbl 0793.00015].

MSC:
 14H25 Arithmetic ground fields for curves 14G15 Finite ground fields in algebraic geometry 14G05 Rational points 11G20 Curves over finite and local fields 14H45 Special algebraic curves and curves of low genus