Abstract:
We consider the following conjectures:
$\operatorname{Hodge}(X)$, $\operatorname{Tate}(X)$
(over a perfect finitely generated field), Grothendieck's standard
conjecture $B(X)$ of Lefschetz type on the algebraicity of the Hodge
operator $\ast$, conjecture $D(X)$ on the coincidence
of the numerical and homological equivalences of algebraic cycles
and conjecture $C(X)$ on the algebraicity of Künneth components of the
diagonal for smooth complex projective varieties.
We show that they are compatible with
monoidal transformations: if one of them holds for a smooth
projective variety $X$ and a smooth closed subvariety
$Y\hookrightarrow X$, then it holds for $X'$, where $f\colon X'\to X$
is the blow up of $X$ along $Y$. All of these conjectures are reduced
to the case of rational varieties.