Holmstrom Proper model category

A model category is left proper if a pushout of a WE under a cofibration is always a WE. Dually, a model category is right proper if a pullback of a WE under a fibration is always a WE. A model category is proper if it is both left proper and right proper.

http://ncatlab.org/nlab/show/proper+model+category

http://golem.ph.utexas.edu/category/2012/05/the_mysterious_nature_of_right.html

Examples of proper model cats: Sset,Sset *,Top,Top *,SptSset, Sset_*, Top, Top_*, Spt, and simplicial abelian groups.

nLab page on Proper model category

Created on June 9, 2014 at 21:16:13 by Andreas Holmström