Toric geometry and the standard conjecture for a compactification of the Néron model of Abelian variety
over $1$-dimensional function field
S. G. Tankeev Vladimir State University
Abstract:
It is proved that if
$\mathcal M\to C$ is the Néron minimal model of a principally polarized
$(d-1)$-dimensional Abelian variety
$\mathcal M_\eta$ over the field
$\kappa(\eta)$ of rational functions of a smooth projective curve
$C$,
$$
\operatorname{End}_{\overline{\kappa(\eta)}} (\mathcal M_\eta\otimes_{\kappa(\eta)}\overline{\kappa(\eta)})=\mathbb Z,
$$
the complexification of the Lie algebra of the Hodge group
$\operatorname{Hg}(M_\eta\otimes_{\kappa(\eta)}\mathbb {C})$ is a simple Lie algebra of type
$C_{d-1}$, all bad reductions of the Abelian variety
$\mathcal M_\eta$ are semi-stable,
for any places
$\delta,\delta'$ of bad reductions
the
$\mathbb Q$-space of Hodge cycles on the product
$\operatorname{Alb}(\overline{\mathcal M_\delta^0})\,\times \, \operatorname{Alb}(\overline{\mathcal M_{\delta'}^0})$ of Albanese varieties
is generated by classes of algebraic cycles,
then
there exists a finite ramified covering
$\widetilde{C}\to C$ such that, for any Künnemann compactification
$\widetilde{X}$
of the Néron minimal model of the Abelian variety $\mathcal M_\eta\otimes_{\kappa(\eta)}\kappa(\widetilde{\eta})$,
the Grothendieck standard conjecture
$B(\widetilde{X})$ of Lefschetz type is true.
Keywords:
toric geometry, Grothendieck standard conjecture of Lefschetz type, Abelian variety,
Künnemann compactification of Néron model, Hodge conjecture.
UDC:
512.7
MSC: 14C25,
14E30,
14F25,
11G10,
14J35 Received: 15.02.2024
DOI:
10.4213/im9581