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Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg : Volume 87

Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg : Volume 86

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Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg : Volume 70

Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg : Volume 70, Issue 1, December 2000

Quadratische Körper über Polynombereichen Galois’scher Felder und ihre Zetafunktionen

Quadratische körper über polynombereichen galois’scher felder und ihre Zetafunktionen

Systems of sets of lengths II

Generalized ℚ-curves and factors of J$_{1}$(N)

On orthogonality-preserving plücker transformations of hyperbolic spaces

On the coincidence of hecke-eigenforms

On a pythagorean-type functional equation with exponent 3 involving finite fields

General blowups of ruled surfaces

On lattice points in rational ellipsoids: An omega estimate for the error term

Isomorphism classes and adjoints of certain iwasawa modules

On hecke eigenforms of degree n

A note on triality and symmetric compositions

Sixteen-dimensional locally compact translation planes admitting SU$_{4}$ℂ · SU$_{2}$ℂ or SU$_{4}$ℂ · SL$_{2}$ℝ as a group of collineations

Characterizations of the ratio of gamma and q-Gamma functions

Stability of the Quadratic Equation of Pexider Type

Special values of triple product L-Functions and nearly holomorphic eisenstein series

On threefolds covered by lines

A propos de la tour localement cyclotomique d’un corps de nombres

A characterization of relativistic addition

A note on graphs with countable automorphism group

Moduli of simple holomorphic pairs and effective divisors

A note on integral bases of unramified cyclic extensions of prime degree

On the functional equation of singular series

Projective representations i. projective lines over rings

Projective representations II. generalized chain geometries

Modular forms of rational weights and modular varieties

Zur verteilung der potenzen ganzer zahlen eines komplexen kubischen zahlkörpers

Two theorems on units of orders

Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg : Volume 69

Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg : Volume 68

Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg : Volume 67

On threefolds covered by lines

Content Provider	Springer Nature Link
Author	Mezzetti, Emilia Portelli, Dario
Copyright Year	2000
Abstract	A classification theorem is given of projective threefolds that are covered by the lines of a two-dimensional family, but not by a higher dimensional family. Precisely, ifX is such a threefold, let Σ denote the Fano scheme of lines onX and μ the number of lines contained inX and passing through a general point ofX. Assume that Σ is generically reduced. Then μ ≤ 6. Moreover,X is birationally a scroll over a surface (μ = 1), orX is a quadric bundle, orX belongs to a finite list of threefolds of degree at most 6. The smooth varieties of the third type are precisely the Fano threefolds with −K $_{ X }$ = 2H $_{ X }$.
Starting Page	211
Ending Page	238
Page Count	28
File Format	PDF
ISSN	00255858
Journal	Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg
Volume Number	70
Issue Number	1
e-ISSN	18658784
Language	English
Publisher	Springer-Verlag
Publisher Date	2000-01-01
Publisher Place	Berlin, Heidelberg
Access Restriction	One Nation One Subscription (ONOS)
Subject Keyword	Algebra Differential Geometry Combinatorics Number Theory Topology Geometry
Content Type	Text
Resource Type	Article
Subject	Mathematics

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