منابع مشابه
Computation of Unirational Fields
One of the main contributions which Volker Weispfenning made to mathematics is related to Gröbner bases theory. In this paper we present an algorithm for computing all algebraic intermediate subfields in a separably generated unirational field extension (which in particular includes the zero characteristic case). One of the main tools is Gröbner bases theory. Our algorithm also requires computi...
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It is no exaggeration to say that the theory of separably injective spaces is quite different from that of injective spaces. In this chapter we will explain why. Indeed, we will enter now in the main topic of the monograph, namely, separably injective spaces and their “universal” version. After giving the main definitions and taking a look at the first natural examples one encounters, we presen...
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We prove that the moduli space A 11 of 1; 11-polarized Abelian surfaces with level structure of canonical type is birational to Klein's cubic hypersurface in P4. Therefore, A 11 is unirational but not rational, and there are no G11-cusp forms of weight 3. The same methods also provide an easy proof of the rationality of A 9 . Mathematics Subject Classi¢cation (2000). 14K10. Key words. Abelian...
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We introduce tropically unirational varieties, which are subvarieties of tori that admit dominant rational maps whose tropicalisation is surjective. The central (and unresolved) question is whether all unirational varieties are tropically unirational. We present several techniques for proving tropical unirationality, along with various examples. 1. Tropical Unirationality Tropical geometry has ...
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In this paper, we determine the perfect subfields over which a field is separably generated. Let a field F of characteristic. p^O be an extension of a field £. A separating transcendence basis for the extension £/£ is a transcendence basis B of £/£ such that £ is a separable algebraic extension of £(£). If £/£ has a separating transcendence basis, we say that £ is separably generated over £. A ...
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ژورنال
عنوان ژورنال: Open Mathematics
سال: 2009
ISSN: 2391-5455
DOI: 10.2478/s11533-008-0058-0