nLab
cospan

Contents

Definition

In any category, a cospan is a diagram like this:

a b f g c \array{ && a &&&& b \\ & && {}_{f}\searrow & & \swarrow_g && \\ &&&& c &&&& }

A cospan that admits a cone is called a quadrable cospan.

A cospan in the category CC is the same as a span in the opposite category C opC^{op}. So, all general facts about cospans in CC are general facts about spans in C opC^{op}, and the reader may turn to the entry on spans to learn more.

See also

Revised on July 22, 2012 02:31:58 by Toby Bartels (98.23.151.73)