nLab quasicategory of fractions

Idea and definition

If CC is a quasicategory and WW is a class of morphisms in CC, then the quasicategory of fractions is a functor L:CC[W 1]L\colon C\to C[W^{-1}] that has the following universal property: precomposition with LL identifies the quasicategory of functors C[W 1]DC[W^{-1}]\to D with the full subquasicategory of functors CDC\to D that sends elements of WW to invertible morphisms in DD.

Terminology

In the existing literature on quasicategories, some sources (like Lurie’s Higher Topos Theory) do not assign a specific name to this concept and simply talk about it by saying that “S 1CS^{-1}C is obtained from CC by inverting the morphisms of SS”. (See Warning 5.2.7.3 in Higher Topos Theory.)

Other sources, like Cisinski‘s Higher Categories and Homotopical Algebra, use the term “localization” to refer to this concept, and refer to localizations in the sense of Lurie as “left Bousfield localizations”.

Last revised on December 26, 2023 at 18:08:55. See the history of this page for a list of all contributions to it.