8,796 research outputs found
Duality of equations and coequations via contravariant adjunctions
In this paper we show duality results between categories of equations and categories of coequations. These dualities are obtained as restrictions of dualities between categories of algebras and coalgebras, which arise by lifting contravariant adjunctions on the base categories. By extending this approach to (co)algebras for (co)monads, we retrieve th
Homotopical Adjoint Lifting Theorem
This paper provides a homotopical version of the adjoint lifting theorem in
category theory, allowing for Quillen equivalences to be lifted from monoidal
model categories to categories of algebras over colored operads. The generality
of our approach allows us to simultaneously answer questions of rectification
and of changing the base model category to a Quillen equivalent one. We work in
the setting of colored operads, and we do not require them to be
-cofibrant. Special cases of our main theorem recover many known
results regarding rectification and change of model category, as well as
numerous new results. In particular, we recover a recent result of
Richter-Shipley about a zig-zag of Quillen equivalences between commutative
-algebra spectra and commutative differential graded
-algebras, but our version involves only three Quillen equivalences
instead of six. We also work out the theory of how to lift Quillen equivalences
to categories of colored operad algebras after a left Bousfield localization.Comment: This is the final, journal versio
Completeness results for quasi-categories of algebras, homotopy limits, and related general constructions
Consider a diagram of quasi-categories that admit and functors that preserve
limits or colimits of a fixed shape. We show that any weighted limit whose
weight is a projective cofibrant simplicial functor is again a quasi-category
admitting these (co)limits and that they are preserved by the functors in the
limit cone. In particular, the Bousfield-Kan homotopy limit of a diagram of
quasi-categories admit any limits or colimits existing in and preserved by the
functors in that diagram. In previous work, we demonstrated that the
quasi-category of algebras for a homotopy coherent monad could be described as
a weighted limit with projective cofibrant weight, so these results immediately
provide us with important (co)completeness results for quasi-categories of
algebras. These generalise most of the classical categorical results, except
for a well known theorem which shows that limits lift to the category of
algebras for any monad, regardless of whether its functor part preserves those
limits. The second half of this paper establishes this more general result in
the quasi-categorical setting: showing that the monadic forgetful functor of
the quasi-category of algebras for a homotopy coherent monad creates all limits
that exist in the base quasi-category, without further assumption on the monad.
This proof relies upon a more delicate and explicit analysis of the particular
weight used to define quasi-categories of algebras.Comment: 33 pages; a sequel to arXiv:1306.5144 and arXiv:1310.8279; v3: final
journal version with updated internal references to the new version of
"Homotopy coherent adjunctions and the formal theory of monads
Examples of finite-dimensional Hopf algebras with the dual Chevalley property
We present new Hopf algebras with the dual Chevalley property by determining
all semisimple Hopf algebras Morita-equivalent to a group algebra over a finite
group, for a list of groups supporting a non-trivial finite-dimensional Nichols
algebra.Comment: Final version. Accepted for publication in Publicacions
Matem\`atique
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
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