2,746 research outputs found
Simplicial presheaves of coalgebras
The category of simplicial R-coalgebras over a presheaf of commutative unital
rings on a small Grothendieck site is endowed with a left proper, simplicial,
cofibrantly generated model category structure where the weak equivalences are
the local weak equivalences of the underlying simplicial presheaves. This model
category is naturally linked to the R-local homotopy theory of simplicial
presheaves and the homotopy theory of simplicial R-modules by Quillen
adjunctions. We study the comparison with the R-local homotopy category of
simplicial presheaves in the special case where R is a presheaf of
algebraically closed (or perfect) fields. If R is a presheaf of algebraically
closed fields, we show that the R-local homotopy category of simplicial
presheaves embeds fully faithfully in the homotopy category of simplicial
R-coalgebras.Comment: 24 page
A necessary and sufficient condition for induced model structures
A common technique for producing a new model category structure is to lift
the fibrations and weak equivalences of an existing model structure along a
right adjoint. Formally dual but technically much harder is to lift the
cofibrations and weak equivalences along a left adjoint. For either technique
to define a valid model category, there is a well-known necessary "acyclicity"
condition. We show that for a broad class of "accessible model structures" - a
generalization introduced here of the well-known combinatorial model structures
- this necessary condition is also sufficient in both the right-induced and
left-induced contexts, and the resulting model category is again accessible. We
develop new and old techniques for proving the acyclity condition and apply
these observations to construct several new model structures, in particular on
categories of differential graded bialgebras, of differential graded comodule
algebras, and of comodules over corings in both the differential graded and the
spectral setting. We observe moreover that (generalized) Reedy model category
structures can also be understood as model categories of "bialgebras" in the
sense considered here.Comment: 49 pages; final journal version to appear in the Journal of Topolog
Cocommutative coalgebras: homotopy theory and Koszul duality
We extend a construction of Hinich to obtain a closed model category
structure on all differential graded cocommutative coalgebras over an
algebraically closed field of characteristic zero. We further show that the
Koszul duality between commutative and Lie algebras extends to a Quillen
equivalence between cocommutative coalgebras and formal coproducts of curved
Lie algebras.Comment: 38 page
Comonadic Coalgebras and Bousfield Localization
For a model category, we prove that taking the category of coalgebras over a
comonad commutes with left Bousfield localization in a suitable sense. Then we
prove a general existence result for left-induced model structure on the
category of coalgebras over a comonad in a left Bousfield localization. Next we
provide several equivalent characterizations of when a left Bousfield
localization preserves coalgebras over a comonad. These results are illustrated
with many applications in chain complexes, (localized) spectra, and the stable
module category
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