Epimorphism

Let be a morphism in Category We say is an epimorphism if

for all We denote epimorphisms by

\usepackage{tikz-cd}
\begin{document}
\begin{tikzcd}
A \arrow[r, two heads, "f"] & B
\end{tikzcd}
\end{document}

In Category of Sets, epimorphisms are surjective.