IF YOU CAN SEE THIS go to http://www.cs.cornell.edu/Info/People/sfa/Nuprl/Shared/Xindentation_hack_doc.html
At:
ring-list R:(Id), in,out:(|R|IdLnk).
ring(R;in;out) (L:|R| List. 0<||L|| & (i:|R|. (iL)))
By:
Auto THEN Unfold `ring` -1 THEN ExRepD THEN RenameVar `i' -1