DOI

We study the kernel of the “compact motivization” functor (formula presented) (i.e., we try to describe those compact objects of the A-linear version of SH(k) whose associated motives vanish; here ℤ ⊂ Λ ⊂ ℚ). We also investigate the question when the 0-homotopy connectivity of (formula presented) ensures the O-homotopy connectivity of E itself (with respect to the homotopy t-structure (formula presented) for SH^(k)). We prove that the kernel of (formula presented) vanishes and the corresponding “homotopy connectivity detection” statement is also valid if and only if A; is a non-orderable field; this is an easy consequence of similar results of T. Bachmann (who considered the case where the cohomological 2-dimension of k is finite). Moreover, for an arbitrary k the kernel in question does not contain any 2-torsion (and the author also suspects that all its elements are odd torsion unless 1/2 € A). Furthermore, if the exponential characteristic of k is invertible in A then this kernel consists exactly of “infinitely effective” (in the sense of Voe-vodsky’s slice filtration) objects of (formula presented). The results and methods of this paper are useful for the study of motivic spectra; they allow extending certain statements to motivic categories over direct limits of base fields. In particular, we deduce the tensor invertibility of motivic spectra of affine quadrics over arbitrary non-orderable fields from some other results of Bachmann. We also generalize a theorem of A. Asok.
Язык оригиналаанглийский
Страницы (с-по)811-840
Число страниц30
ЖурналDocumenta Mathematica
Том25
DOI
СостояниеОпубликовано - 1 янв 2020

ID: 125931547