The ** nLab** is a wiki for research-level notes, expositions and collaborative work, including original research, in mathematics, physics, and philosophy, with a focus on methods from type theory, category theory, and homotopy theory. The

*n*Lab espouses the "

*n*-point of view"

^{[1]}(a deliberate pun on Wikipedia's "neutral point of view") that type theory, homotopy theory, category theory, and higher category theory provide a useful unifying viewpoint for mathematics, physics and philosophy. The

*n*in

*n*-point of view could refer to either

*n*-categories as found in higher category theory,

*n*-groupoids as found in both homotopy theory and higher category theory, or

*n*-types as found in homotopy type theory.

## Overview

The *n*Lab was originally conceived to provide a repository for ideas (and even new research) generated in the comments on posts at the *n*-Category Café, a group blog run (at the time) by John C. Baez, David Corfield and Urs Schreiber. Eventually the *n*Lab developed into an independent project, which has since grown to include whole research projects and encyclopedic material.^{[2]}

Associated to the *n*Lab is the nForum, an online discussion forum for announcement and discussion of *n*Lab edits (the analog of Wikipedia's "talk" pages) as well as for general discussion of the topics covered in the *n*Lab. The preferred way of contacting the *n*Lab steering committee is to post on the nForum.^{[3]} An experimental sub-project of the *n*Lab is the *Publications of the *n*Lab*, intended as a journal for refereed research articles that are published online and cross-hyperlinked with the main wiki.

The *n*Lab was set up on November 28, 2008 by Urs Schreiber using the Instiki software provided and maintained by Jacques Distler. Since May 2015 it runs on a server at Carnegie Mellon University that is funded in the context of Steve Awodey's Homotopy Type Theory MURI grant.^{[4]} The system administrator is Richard Williamson. The domain ncatlab.org is owned by Urs Schreiber.

The *n*Lab is listed on MathOverflow as a standard online mathematics reference to check before asking questions.^{[5]} Many questions and answers link to the *n*Lab for background material.^{[6]} It is one of two wikis mentioned by the mathematical physicist John C. Baez in his review of math blogs for the American Mathematical Society.^{[7]}

There is an informal steering committee, which "doesn't run the *n*Lab",^{[8]} but exists in order to resolve issues that would cause the whole project to run into trouble.

## See also

## References

**^***n*POV in*n*Lab**^**Urs Schreiber, What is... the nLab?**^**Steering committee in*n*Lab meta**^**Awodey, Steve (29 April 2014). "HoTT awarded a MURI".*Homotopy Type Theory*. Retrieved 8 August 2020.**^**MathOverflow, 1.0 'How to ask' page. Archived on 2013-06-04.**^**MathOverflow, Results for a search for 'nlab'. As of 2018-12-11 there are over 800 results.**^**John C. Baez, "Math Blogs",*Notices of the American Mathematical Society*, March 2010**^**Steering committee in*n*Lab meta