Diophantine approximations on projective spaces
Diophantine approximations on projective spaces
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射影空间上的丢番图近似
DOI:
10.1007/bf01231559
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发表时间:
1994
影响因子:
3.1
通讯作者:
G. Wüstholz
中科院分区:
文献类型:
--
作者:
G. Faltings;G. Wüstholz
In this paper we study diophantine approximations on projective spaces of arbitrary dimension. Especially we give a new proof for the results of WM Schmidt. Historically diophantine approximation has been the method for proving finiteness results in diophantine geometry. In the case of the projective line the fundamental result is Roth's theorem. This has been generalized to higher dimension by Schmidt. His basic result is the subspace theorem (see [$2]). However the proof is very complicated and involved. It relates on deep results in the geometry of numbers.Recently a new development in the theory was started by Vojta which lead to a breakthrough for diophantine approximations on abelian varieties. He found a new way to use heights and the theorem of Mordell and Weil. His main insight was that on products of abelian varieties one has many more line bundles than just the product bundles. His discovery inspired Faltings to find a new general result in the theory of diophantine approximations, the product theorem. It very much simplifies the theory and its application to abelian varieties lead to some generalization of Mordell's conjecture (see [-Fa]). As a second application Faltings also gave a lower bound for the distance of a rational point to a hypersurface on an abelian variety. In the present paper we study the consequences of the product theorem in the more classical case of projective spaces. Here not so many line bundles are available as for abelian varieties. Therefore the results will be much weaker in general. However in the case Schmidt is considering the result is best possible up to an e. The advantage in the present situation is that we do not have to cope with complicated line bundles as in the abelian case; this simplifies the proofs considerably. On the other hand the estimates one needs have to be much more precise. In order to obtain the best possible exponents in the approximation theorems we have to be very careful. Now let us explain our results. We fix a number field K and chose a subvariety Ecn~" defined over K and study the distance d,,(E; x) of a K-rational point