nLab
cobase change

Contents

Definition

Cobase change is another term for pushout of a morphism:

if

X U Y Y XU \array{ X &\to & U \\ \downarrow && \downarrow \\ Y &\to& Y \sqcup_X U }

is a pushout square in some category then the morphism UU XYU \to U \sqcup_X Y is the cobase change or cobase extension of XYX \to Y along XUX \to U.

Remarks

Revised on May 19, 2010 09:09:08 by Urs Schreiber (131.211.232.167)