# Contents

## Definition

###### Definition

If a category $C$ carries a model category structure, then the opposite category $C^{op}$ carries the opposite model structure:

its weak equivalences are those morphisms whose dual was a weak equivalence in $C$, its fibrations are those morphisms that were cofibrations in $C$ and its cofibrations are those that were fibrations in $C$.

Created on February 6, 2013 at 18:01:30. See the history of this page for a list of all contributions to it.