O. T. Izhboldin

摘要

For any $nge3$, we construct a field $F$ and an $n$-foldPfister form $arphi$such that the field extension $F(arphi)/F$ is not excellent.We prove that $F(arphi)/F$ is universally excellent if and only if$arphi$ is a Pfister neighbor of dimension $le4$.