Parton Distribution Functions
  The parton distribution functions (PDFs) of the proton, a necessary input to almost all theory predictions for hadron colliders, are reviewed in this document. An introduction to the PDF determination by global analyses of the main PDF fitting groups with an emphasis on HERA PDFs is presented. Finally, theory predictions based on different PDFs are compared to some recent relevant LHC and Tevatron measurements. 
Ringaile Placakyte (for the H1 Collaboration and for the ZEUS   Collaboration)
hep-ph hep-ex