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A 4₃ configuration of lines and conics in ℙ⁵

Tomasz Szemberg (1994)

Annales Polonici Mathematici

Studying the connection between the title configuration and Kummer surfaces we write explicit quadratic equations for the latter. The main results are presented in Theorems 8 and 16.

A Bogomolov property for curves modulo algebraic subgroups

Philipp Habegger (2009)

Bulletin de la Société Mathématique de France

Generalizing a result of Bombieri, Masser, and Zannier we show that on a curve in the algebraic torus which is not contained in any proper coset only finitely many points are close to an algebraic subgroup of codimension at least 2 . The notion of close is defined using the Weil height. We also deduce some cardinality bounds and further finiteness statements.

A bound for the average rank of a family of abelian varieties

Rania Wazir (2004)

Bollettino dell'Unione Matematica Italiana

In this note, we consider a one-parameter family of Abelian varieties A / Q T , and find an upper bound for the average rank in terms of the generic rank. This bound is based on Michel's estimates for the average rank in a one-parameter family of Abelian varieties, and extends previous work of Silverman for elliptic surfaces.

A bound for the Milnor number of plane curve singularities

Arkadiusz Płoski (2014)

Open Mathematics

Let f = 0 be a plane algebraic curve of degree d > 1 with an isolated singular point at 0 ∈ ℂ2. We show that the Milnor number μ0(f) is less than or equal to (d−1)2 − [d/2], unless f = 0 is a set of d concurrent lines passing through 0, and characterize the curves f = 0 for which μ0(f) = (d−1)2 − [d/2].

A boundedness theorem for morphisms between threefolds

Ekatarina Amerik, Marat Rovinsky, Antonius Van de Ven (1999)

Annales de l'institut Fourier

The main result of this paper is as follows: let X , Y be smooth projective threefolds (over a field of characteristic zero) such that b 2 ( X ) = b 2 ( Y ) = 1 . If Y is not a projective space, then the degree of a morphism f : X Y is bounded in terms of discrete invariants of X and Y . Moreover, suppose that X and Y are smooth projective n -dimensional with cyclic Néron-Severi groups. If c 1 ( Y ) = 0 , then the degree of f is bounded iff Y is not a flat variety. In particular, to prove our main theorem we show the non-existence of a flat 3-dimensional...

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