Nori-Motive und Tannaka-Theorie
  In the late 90s M. V. Nori constructed a category of motives in charakteristic 0. Using a directed graph with a representation into noetherian R-Modules, he defined a universal R-linear abelian category, called diagram category.The following paper describes this construction and gives proof to the necessary universal property. In addition we establish a criteria for the diagram category to be a category of finitely generated modules over a certain coalgebra. Finally we sketch the connection between the diagram category and the representations of affine group schemes (Tannaka-Dualism) and define the category of mixed Nori-Motives. 
Jonas von Wangenheim
math.AG math.CT