Units in Grothendieck-Witt rings and A^1-spherical fibrations
arXiv:1304.5922
Abstract
In this note, we show that the units in Grothendieck-Witt rings extend to an unramified strictly A^1-invariant sheaf of abelian groups on the category of smooth schemes. This implies that there is an A^1-local classifying space of spherical fibrations.
19 pages