Résume | As we will explain using Feynman cagtegories, there is a hierarchy objects, algebras, operads, which gives rise to a secondary hierarchy, modules, algebras over operads and hyperoperads --- all heavily used in algebraic topology. Through a W construction, we can even make a priori combinatorial objects into topological cell complexes. This for instance realises moduli spaces of curves with marked points. The niceness condition is satisfied for so-called quadratic/cubical Feynman categories. This leads into the field of quadratic algebras and operads using the second hierarchy as we will discuss. Another surprising structure, which is the last subject, we would like to touch upon, is a connection to Hopf algebras, for any reasonably nice Feynman category defines a Hopf algebra structure. |