David Z. Kumallagov

Uniform Rost nilpotence and birational motives

For a field extension $E/k$ and a Chow motive $M$, let $I_E(M)=\ker\bigl(\operatorname{End}_k(M)\longrightarrow \operatorname{End}_E(M_E)\bigr)$ be the base-change ideal. We establish explicit nilpotence bounds for these ideals in several geometric settings. We also prove effective generic descent: if $M$ is a summand...