Graded and Filtered Fiber Functors on Tannakian Categories
  We study fiber functors on Tannakian categories which are equipped with a grading or a filtration. Our goal is to give a comprehensive set of foundational results about such functors. A main result is that each filtration on a fiber functor can be split by a grading fpqc-locally on the base scheme. 
Paul Ziegler
math.AG