932 research outputs found
Mixed motivic sheaves (and weights for them) exist if 'ordinary' mixed motives do
The goal of this paper is to prove: if certain 'standard' conjectures on
motives over algebraically closed fields hold, then over any 'reasonable'
there exists a motivic -structure for the category of Voevodsky's
-motives (as constructed by Cisinski and Deglise). If is 'very
reasonable' (for example, of finite type over a field) then the heart of this
-structure (the category of mixed motivic sheaves over ) is endowed with
a weight filtration with semi-simple factors. We also prove a certain 'motivic
decomposition theorem' (assuming the conjectures mentioned) and characterize
semi-simple motivic sheaves over in terms of those over its residue fields.
Our main tool is the theory of weight structures. We actually prove somewhat
more than the existence of a weight filtration for mixed motivic sheaves: we
prove that the motivic -structure is transversal to the Chow weight
structure for -motives (that was introduced previously and independently by
D. Hebert and the author; weight structures and their transversality with
t-structures were also defined by the author in recent papers). We also deduce
several properties of mixed motivic sheaves from this fact. Our reasoning
relies on the degeneration of Chow-weight spectral sequences for 'perverse
'etale homology' (that we prove unconditionally); this statement also yields
the existence of the Chow-weight filtration for such (co)homology that is
strictly restricted by ('motivic') morphisms.Comment: a few minor corrections mad
Relative continuous K-theory and cyclic homology
We show that for an associative algebra A and its ideal I such that the
I-adic topology on A coincides with the p-adic topology, the relative
continuous K-theory pro-spectrum "lim"K(A_i, IA_i), where A_i :=A/p^i A, is
naturally isogenous to the cyclic chain pro-complex "lim"CC(A_i) (subject to
minor conditions on A). This identification is a continuous version of the
classical Goodwillie isomorphism. The work comes from an attempt to understand
the article of Bloch, Esnault, and Kerz "p-adic deformations of algebraic cycle
classes".Comment: 26 pages. The section about pro-spectra is corrected. To appear in
the Munster Journal of Mathematic
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