scholarly journals Finiteness theorems for K3 surfaces and abelian varieties of CM type

2018 ◽  
Vol 154 (8) ◽  
pp. 1571-1592 ◽  
Author(s):  
Martin Orr ◽  
Alexei N. Skorobogatov
Keyword(s):  
Abelian Varieties ◽  
Algebraic Closure ◽  
Complex Multiplication ◽  
Uniform Boundedness ◽  
Invariant Subgroup ◽  
Smooth Projective Variety ◽  
Number Fields ◽  
K3 Surfaces ◽  
Isomorphism Classes ◽  
Finiteness Theorems

We study abelian varieties and K3 surfaces with complex multiplication defined over number fields of fixed degree. We show that these varieties fall into finitely many isomorphism classes over an algebraic closure of the field of rational numbers. As an application we confirm finiteness conjectures of Shafarevich and Coleman in the CM case. In addition we prove the uniform boundedness of the Galois invariant subgroup of the geometric Brauer group for forms of a smooth projective variety satisfying the integral Mumford–Tate conjecture. When applied to K3 surfaces, this affirms a conjecture of Várilly-Alvarado in the CM case.

Growth of Selmer Groups of CM Abelian Varieties

2015 ◽  
Vol 67 (3) ◽  
pp. 654-666 ◽  
Author(s):  
Meng Fai Lim ◽  
V. Kumar Murty
Keyword(s):  
Abelian Varieties ◽  
Complex Multiplication ◽  
Number Fields ◽  
Selmer Groups

AbstractLet p be an odd prime. We study the variation of the p-rank of the Selmer groups of Abelian varieties with complex multiplication in certain towers of number fields.

scholarly journals Computing abelian varieties over finite fields isogenous to a power

2019 ◽  
Vol 5 (4) ◽  
Author(s):  
Stefano Marseglia
Keyword(s):  
Characteristic Polynomial ◽  
Finite Fields ◽  
Abelian Varieties ◽  
Number Fields ◽  
Explicit Description ◽  
Finite Product ◽  
Real Roots ◽  
Isomorphism Classes ◽  
Ordinary Case ◽  
Theoretic Description

Abstract In this paper we give a module-theoretic description of the isomorphism classes of abelian varieties A isogenous to $$B^r$$Br, where the characteristic polynomial g of Frobenius of B is an ordinary square-free q-Weil polynomial, for a power q of a prime p, or a square-free p-Weil polynomial with no real roots. Under some extra assumptions on the polynomial g we give an explicit description of all the isomorphism classes which can be computed in terms of fractional ideals of an order in a finite product of number fields. In the ordinary case, we also give a module-theoretic description of the polarizations of A.

scholarly journals PERIODS OF DRINFELD MODULES AND LOCAL SHTUKAS WITH COMPLEX MULTIPLICATION

2018 ◽  
Vol 19 (1) ◽  
pp. 175-208 ◽  
Author(s):  
Urs Hartl ◽  
Rajneesh Kumar Singh
Keyword(s):  
Present Article ◽  
Abelian Varieties ◽  
Complex Multiplication ◽  
Number Fields ◽  
Product Formula ◽  
Drinfeld Modules ◽  
Higher Dimensional ◽  
Carlitz Module ◽  
Logarithmic Derivatives ◽  
Faltings Height

Colmez [Périodes des variétés abéliennes a multiplication complexe,Ann. of Math. (2)138(3) (1993), 625–683; available athttp://www.math.jussieu.fr/∼colmez] conjectured a product formula for periods of abelian varieties over number fields with complex multiplication and proved it in some cases. His conjecture is equivalent to a formula for the Faltings height of CM abelian varieties in terms of the logarithmic derivatives at$s=0$of certain Artin$L$-functions. In a series of articles we investigate the analog of Colmez’s theory in the arithmetic of function fields. There abelian varieties are replaced by Drinfeld modules and their higher-dimensional generalizations, so-called$A$-motives. In the present article we prove the product formula for the Carlitz module and we compute the valuations of the periods of a CM$A$-motive at all finite places in terms of Artin$L$-series. The latter is achieved by investigating the local shtukas associated with the$A$-motive.

scholarly journals A note on moduli spaces of conformal classes for flat tori of higher dimension and on their conformal multiplication

2021 ◽  
Author(s):  
Anna Gori ◽  
Alberto Verjovsky ◽  
Fabio Vlacci
Keyword(s):  
Moduli Space ◽  
Moduli Spaces ◽  
Abelian Varieties ◽  
Complex Multiplication ◽  
Higher Dimension ◽  
Geometric Constructions ◽  
Flat Torus ◽  
Flat Tori

AbstractMotivated by the theory of complex multiplication of abelian varieties, in this paper we study the conformality classes of flat tori in $${\mathbb {R}}^{n}$$ R n and investigate criteria to determine whether a n-dimensional flat torus has non trivial (i.e. bigger than $${\mathbb {Z}}^{*}={\mathbb {Z}}{\setminus }\{0\}$$ Z ∗ = Z \ { 0 } ) semigroup of conformal endomorphisms (the analogs of isogenies for abelian varieties). We then exhibit several geometric constructions of tori with this property and study the class of conformally equivalent lattices in order to describe the moduli space of the corresponding tori.

scholarly journals Cycles in the de Rham cohomology of abelian varieties over number fields

2018 ◽  
Vol 154 (4) ◽  
pp. 850-882
Author(s):  
Yunqing Tang
Keyword(s):  
Endomorphism Ring ◽  
Abelian Varieties ◽  
Number Fields ◽  
De Rham Cohomology ◽  
Tate Conjecture ◽  
De Rham ◽  
Prime Dimension

In his 1982 paper, Ogus defined a class of cycles in the de Rham cohomology of smooth proper varieties over number fields. This notion is a crystalline analogue of$\ell$-adic Tate cycles. In the case of abelian varieties, this class includes all the Hodge cycles by the work of Deligne, Ogus, and Blasius. Ogus predicted that such cycles coincide with Hodge cycles for abelian varieties. In this paper, we confirm Ogus’ prediction for some families of abelian varieties. These families include geometrically simple abelian varieties of prime dimension that have non-trivial endomorphism ring. The proof uses a crystalline analogue of Faltings’ isogeny theorem due to Bost and the known cases of the Mumford–Tate conjecture.

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