Subject: To Stasheff on Grothendieck characterization of nerves From: Pascal Lambrechts Date: Mon, 5 Dec 2005 12:51:18 +0100 > > Subject: nerves > From: jim stasheff > Date: Fri, 02 Dec 2005 10:41:25 -0500 > > Does anyone know a reference for > grothedieck's characterization for when a simplicial set > is the nerve of a groupoid > or if anyone observed it earlier? > > jim Dear Jim There is some reference in Graeme Segal "Classifying spaces and spectral sequences" (Publ. IHES): see beginning of Section 2, p.106. It makes a reference to Grothendieck "Theorie de la descente" Seminaire Bourbaki 195 (1959-1960) that I didn't check. Hope this helps. Pascal Pascal Lambrechts Institut Mathématique Chemin du cyclotron, 2 B-1348 Louvain-la-Neuve BELGIUM Phone +32 (0)10 473161 Fax +32 (0)10 472530 email: lambrechts@math.ucl.ac.be