Compactifications of the period space of Enriques surfaces Part I
Compactifications of the period space of Enriques surfaces Part I
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Enriques 曲面周期空间的紧化第一部分
DOI:
10.1007/bf02571372
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发表时间:
1991
影响因子:
0.8
通讯作者:
H. Sterk
中科院分区:
文献类型:
--
作者:
H. Sterk
This paper is the first of two papers dealing with compactifications of the period space of Enriques surfaces which are of geometric intcrcst. The motivation for this work comes from two origins. One is the work of Shah [24] on projective degenerations of Enriques surfaces. The other is the work of Looijenga [14, 15] on new compactification techniques for locally symmetric varieties. Shah's paper can be interpreted as dealing with the moduli aspect (it is phrased in terms of Mumford's geometric invariant theory [16]), whereas Looijenga's work refers to the period space aspect. Our ultimate aim then is to describe a compactification of the period space of Enriques surfaces which accounts for Shah's results. This turns out to be a normalized blow-up of the Satake-Baily-Borel compactification along the closure of the divisor describing periods of'special'Enriques surfaces (see w for the notion of a'special'Enriques surface). The period space which we use is of the form D/F where D is a bounded symmetric domain of type IV and dimension 10 and F is some arithmetic group (see w Such a situation also occurred in the work of Horikawa [11, 12] and Namikawa [17] on Enriques surfaces. It should be pointed out, however, that our group is smaller than theirs. The reason is that we wish to take into account the specific geometric setting of Shah's approach ie, we think of our Enriques surfaces as being endowed with an (almost) polarization (of degree 2), which realizes the K3 cover as the minimal resolution of a branched double cover of Y', 0= p1 x P~ or a quadratic cone~ c p3. The degree of the resulting map between the two spaces, 27 9 17-31 (w expresses the fact that a'general'Enriques surface (in the sense of [2]) can be given, up to automorphisms, an (almost) polarization of degree 2 in 27 9 17-31 different ways. We then expect this geometric background to be at least partially reflected in, for instance, the Satake-Baily-Borel compactification of the period space ([21, 22] and [1]). We
影响因子:
3.1
作者:
I. Dolgachev;I. Dolgachev
通讯作者:
I. Dolgachev;I. Dolgachev