# Contents

## Definition

In a model category, an acyclic fibration or trivial fibration is a morphism which is both a fibration and a weak equivalence.

Dually, an acyclic cofibration or trivial cofibration is a morphism which is both a cofibration and a weak equivalence.

## Examples

Revised on February 11, 2013 19:32:24 by Urs Schreiber (89.204.138.151)