Abelian scheme

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A smooth group scheme over a base scheme , the fibres of which are Abelian varieties (cf. Abelian variety). The following is an equivalent definition: An Abelian scheme over , or an Abelian -scheme, is a proper smooth group -scheme all fibres of which are geometrically connected. Intuitively, an Abelian -scheme may be understood as a family of Abelian varieties parametrized by the scheme . A number of fundamental properties of Abelian varieties carry over to Abelian schemes. For instance, an Abelian -scheme is a commutative group -scheme [1], and if is a normal scheme, is projective over , [2].

Abelian schemes are used in the context of moduli schemes of Abelian varieties with various auxiliary structures, and also in the theory of reduction of Abelian varieties (cf. Néron model).


[1] D. Mumford, "Geometric invariant theory" , Springer (1965)
[2] M. Raynaud, "Faisceaux amples sur les schémas en groupes et les espaces homogénes" , Springer (1970)
How to Cite This Entry:
Abelian scheme. I.V. Dolgachev (originator), Encyclopedia of Mathematics. URL:
This text originally appeared in Encyclopedia of Mathematics - ISBN 1402006098