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 $C$, $\End_{\overline{\kappa(\eta)}} (\mathcal M_\eta\otimes_{\kappa(\eta)}\overline{\kappa(\eta)})=\Z$, the complexification of the Lie algebra of the Hodge group $\Hg(M_\eta\otimes_{\kappa(\eta)}\C)$ 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 $\Q$-space of Hodge cycles on the product $\Alb(\overline{\mathcal M_\delta^0})\,\times \, \Alb(\overline{\mathcal M_{\delta'}^0})$ 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,, Kunnemann compactification of Neron model, Hodge conjecture