nLab cobase change

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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.

Last revised on January 2, 2023 at 12:33:43. See the history of this page for a list of all contributions to it.