Dwyer-Kan localization revisited

A version of Dwyer-Kan localization in the context of infinity-categories and simplicial categories is presented. Some results of the classical papers by Dwyer and Kan on simplicial localization are reproven and generalized. It is proven that a Quillen pair of model categories gives rise to an adjoint pair of the DK localizations. Also a result on localization of a family of infinity-categories is proven. This, in particular, is applied to localization of symmetric monoidal infinity-categories, where some (partial) results are obtained.Comment: 24 pages, the final version, accepted to "Homology, Homotopy and Applications

Descent of Deligne groupoids

To any non-negatively graded dg Lie algebra $g$ over a field $k$ of characteristic zero we assign a functor $\Sigma_g: art/k \to Kan$ from the category of commutative local artinian $k$-algebras with the residue field $k$ to the category of Kan simplicial sets. There is a natural homotopy equivalence between $\Sigma_g$ and the Deligne groupoid corresponding to $g$. The main result of the paper claims that the functor $\Sigma$ commutes up to homotopy with the "total space" functors which assign a dg Lie algebra to a cosimplicial dg Lie algebra and a simplicial set to a cosimplicial simplicial set. This proves a conjecture of Schechtman which implies that if a deformation problem is described ``locally'' by a sheaf of dg Lie algebras $g$ on a topological space $X$ then the global deformation problem is described by the homotopy Lie algebra $R\Gamma(X,g)$.Comment: Minor corrections made AMSLaTeX v 1.2 (Compatibility mode