\contentsline {section}{\numberline {1}Basic Notions and Notations}{1}
\contentsline {section}{\numberline {2}Categories and Functors}{2}
\contentsline {section}{\numberline {3}Duality}{7}
\contentsline {section}{\numberline {4}On the Inside of Categories}{8}
\contentsline {section}{\numberline {5}Algebras}{14}
\contentsline {section}{\numberline {6}Co-Algebras}{17}
\contentsline {section}{\numberline {7}Di-Algebras}{20}
\contentsline {section}{References}{23}