Pushout
= Pushout
{title2=$B\sqcup_A C$}
The <colimit> of two arrows $A\to B$ and $A\to C$. A map from the pushout is uniquely a pair of maps from $B$ and $C$ agreeing on $A$. In modules it is $(B\oplus C)/\{(f(a),-g(a)):a\in A\}$.
= Pushout
{title2=$B\sqcup_A C$}
The <colimit> of two arrows $A\to B$ and $A\to C$. A map from the pushout is uniquely a pair of maps from $B$ and $C$ agreeing on $A$. In modules it is $(B\oplus C)/\{(f(a),-g(a)):a\in A\}$.